BIBECHANA Vol. 20, No. 1, April 2023, 65-75 ISSN 2091-0762 (Print), 2382-5340 (Online) Journal homepage: http://nepjol.info/index.php/BIBECHANA Publisher:Dept. of Phys., Mahendra Morang A. M. Campus (Tribhuvan University)Biratnagar A brief review on preparation and application of MWCNT-based polymer nanocomposites Jyoti Giri1,2,3,∗, Rameshwar Adhikari2,4 1Dept. of Chemistry, Tri-Chandra Multiple Campus, Tribhuvan University Kathmandu, Nepal 2Nepal Polymer Institute (NPI), P. O. Box 24411, Kathmandu, Nepal 3Nepal Development and Research Institute (NDRI), Lalitpur, Nepal 4Research Centre for Applied Science and Technology (RECAST), Tribhuvan University Kirtipur, Kathmandu, Nepal ∗Corresponding author. Email: girijys@yahoo.com Abstract Technological advancementalways seeks new materials with improved functional properties, particularly for smart applications. In this regard, nanotechnology is offering today wide range of novel material designs fabricated by compounding nanofillers into the polymer ma- trix. Different allotropic forms of carbon can reinforce the properties of polymers for various applications. Reinforcement depends on the dimension, shape, size and compatibility of the nanofiller with the polymer matrix. Chemical modification of filler surfaces and the matrix can selectively localize the filler in the hybrid composites in the desired phase or at the in- terface by melt mixing or solution casting method, during compounding procedure. In this regard, the conducting nature of the additioin of multiwalled carbon nanotubes (MWCNTs) into a polymer matrix fosters the conductivity into the materials. Such nanocomposites can be used for numerous applications such as conducting materials, super-capacitors, light emitting devices, medical purposes etc,. This review paper focuses on different methods of preparation of MWCNT/polymer nanocomposites, their surface properties, and microbial properties etc,. Keywords Multiwalled carbon nanotubes (MWCNT); Polymer composites; Conductivity; Mechanical strength; Antibacterial properties. Article information Manuscript received: January 16, 2023; Accepted: April 1, 2023 DOI https://doi.org/10.3126/bibechana.v20i1.53724 This work is licensed under the Creative Commons CC BY-NC License. https://creativecommons. org/licenses/by-nc/4.0/ 1 Introduction The advancing world is the gift of nanotechnol- ogy which deals specially with nanomaterial and nanocomposites. They are multiphase materials in which one or more phases of material is in nanoscale dimensions below 100 nm [1–3]. Gener- ally, a nanocomposite material has dispersing phase 65 http://nepjol.info/index.php/BIBECHANA girijys@yahoo.com https://doi.org/10.3126/bibechana.v20i1.53724 https://creativecommons.org/licenses/by-nc/4.0/ https://creativecommons.org/licenses/by-nc/4.0/ Jyoti Giri and Rameshwar Adhikari/ BIBECHANA 20 (2023) 65-75 66 called a matrix and a dispersed or reinforcing phase called a filler. These nanoscaled fillers are em- bedded in a continuous phase of polymer, metal or ceramics matrix [4]. Almost all varieties of polymers are used as matrices such as thermoplas- tics; polyurethane (PU) [5], polyethylene (PE) [6], polyvinyl chloride (PVC) [7], thermosets; epoxy polyimide [8] and phenolic resin [9] and elastomers; polybutadiene (PB) [10], ethylene-octene copoly- mer (EOC) [11]. These fillers may be of 0 dimen- sional (0D), one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D). 3D particles are cubical or spherical structures spread in x, y and z directions for instance boehmite [11], silica [12] and different kinds of particle. 2D particles are sheet-like layered particles spread in x and y direc- tions for instance graphite. 1D particles are tubu- lar or cylindrical in the structure such as single- walled (SWCNT), multiwalled carbon nanotubes (MWCNT) whereas 0D are the quantum dots which are very minute particles comprising few atoms such as fullerenes, polyhedral oligomeric silsesquioxane (POSS) etc., [9–13]. The filler and matrix phases together generally give the synergetic effect to the composites which would be novel, intense and cumulated. The prop- erties of the composites depend on the types of vari- ables i.e., filler, their nanoscale dimension, loading degree, degree of dispersion, their size, shape, ori- entation and interaction with the matrix. Surface area to volume ratio (A/V) with aspect ratio [a= ratio of length (l) and diameter (d)] of filler gives a good relation for the reinforcement in the composite which has been depicted in Fig. 1, in which the change in the aspect ratio of a cir- cular plate with A/V ratio was illustrated. The periodic increase in l of the platelets changes the molecule to a cylindrical form. In region A the platelete on increasing l , structure changes from 1 to 2 and 3. Stage 3 is the one when its l=d and its aspect ratio becomes 1. Further increase in l can be seen in region B, where the structure con- verts to filamental fibrous 1-dimensional structure, stage 4 [14]. Fibers (such as carbon nanotubes, 1 dimensional) and platelets (such as layered silicates clay, 2 dimensional filler) have higher A/V ratios so they have high reinforcement ability [15]. Therefore increasing order of reinforcement can be illustrated with respect to A/V ratio as 1>2>3 [11]. Depending upon the particle size of the filler, electrical, thermal, and optical properties of the nanocomposites can be varied. The interacting phases can even alter the mechanical property of the composite by varying the modulus and strength [16]. Fig. 2 and Fig. 3 show the expanded interfa- cial surface of the filler to interact with the matrix [14]. The spherical fullerence being 3-dimensional has less tendency for agglomeration, less likely is for tubular MWCNT and sheet of graphite has least reinforcement and has possibility of agglom- eration [17–19]. The nanofillers mostly in practice are alumnosil- icates (clays) [20], carbon nanotubes (CNT) [8,21], nanofibres [22], ultra-dispersed diamonds (nanodi- amonds) [23], fullerenes [24], other inorganic nan- otubes, nanoparticles of silicon oxide (SiO2), cal- cium carbonate (CaCO3), metal nanoparticles as well as fibers from biological resources. Different al- lotropic forms of carbon have various effects in the matrix mostly for their strength, conductivity and optical property. Boeing: 787 Dreamliner, the air- craft is an example of mechanical reinforcement. It was made up of carbon fiber-reinforced epoxy resin. Here carbon fiber induced strength and stiffness to the material and epoxy binds the fiber with sig- nificant less weight [25]. The conducting materials form the important base of industries in informa- tion technology, electronics and electrical industries etc., [26]. Conducting fillers in polymers result the conductive composites which have low density, low weight, high mechanical performance, low cost and easy processability such as biobased polymer (from polylactic acid (PLA) and potato starch) and CNTs are one of the most interesting materials with high strength [8, 27]. The sp2 hybridization of the carbon in CNT’s form an allotropic tubular structure that can be termed into diverse architectures to form SWCNT, MWCNT, nanobud etc. Such carbon materials are conductive even in little amount and open differ- ent avenues of applications as polymer compos- ites. Therefore, numerous researchers are in the process throughout the world to achieve optimum best-conducting polymer composites for advanced applications. MWCNT has been incorporated into different polymers such as ethylene vinyl acetate copolymer (EVA) [28], PU block [29], polystyrene (PS)/polyvinylidene fluoride (PVDF) composites [28], polyolefins [29] and polyesters [30–32]. In these systems, electrical-conducting properties, thermal, morphological, mechanical and dielectric properties are enhanced. MWCNT also worked as a compati- bilizer between PS and PVDF [30]. The allotropes of carbon/polymeric nanocom- posites have significant applications in numerous field nowadays. They can be used as antistatic materials [33–35], super capacitors [ [29, 35] highly conductive application (electrodes in touch screens and sensors) [28,36,37] security application, screen printing, coating materials, organic solar cells [29], printing electrodes, conductive adhesives, current limiting devices, shielding for electromagnetic pro- tection, heater with distributed heat emission and self-regulated heaters [27, 29]. Similarly light emit- ting device, contact bottoms of computers, lap- tops, mobiles, I-pads and media techniques etc. X. Jyoti Giri and Rameshwar Adhikari/ BIBECHANA 20 (2023) 65-75 67 Zhao et al., studied carbon black nanoparticles in polystyrene (PS)/polyvinylidene fluoride (PVDF) composites which induce dielectric property. [34] S. B. Kondawar also mentioned that conducting nanocomposites are the noble electrodes for the ap- plication as super capacitor [32]. Electronic tattoo are also some noble application of such nanocom- posites [38,39]. 2 Preparation of conducting polymer nanocomposites There are many techniques for compounding poly- mer matrix with nanofiller. Some of the techniques are explained here [32]. 2.1 Solution casting This is a technique where both polymer and filler are homogeneously dissolved in a solvent separately and mixed followed with sonication. The mixer so- lution is sonicated and cast to a desired shape and the solvent will be slowly evaporated to get a thin film of the composite [38,40]. 2.2 in-situ polymerization This is a technique by which the first polymer was synthesized. During the synthesis of polymer, at the stage of prepolymer formation fillers are incor- porated and stirred well, stabilized and moulded to the desired shape. Usually, the process is applicable for co-polymer with bigger units [37]. 2.3 Internal melt mixing The dried polymer and fillers are blended into the rotors with specific rotation per minute (rpm), tem- perature and for a specific time to homogeneous compounding. Depending upon the type of polymer and composites they are pre-cured and post-cured in an oven at a specific temperature. The stable composites are moulded with hydraulic pressure to obtain a plaque [18,32,33]. 2.4 Twin screw extruder In this technique, dried polymers and fillers are premixed and put into a conical counter rotating a Brabender with the specific speed (round per minute, rpm) of twin extruders at a higher tempera- ture below the melting point. Composites prepared are cooled with ice water to pelletized or prepared the plates with hydrolytic pressure in the specific diameter of moulds [41–46]. Except for the process described above Peng et al., 2008, explained the chemical synthesis, elec- trochemical deposition and co-deposition methods to prepare conducting polymers with carbon nan- otubes. These composites have a high charg- ing/discharging ratio so were applicable to prepare supercapacitors, batteries and fuel cells. [36]. ma- terial on the GCE electrode and (V) represent the operating voltage. 3 Morphological Features of MWCNT- based Nanocomposites The morphology of the nanofiller has many ef- fects on the nanocomposites. Their dispersion and interaction with the matrix play a very impor- tant role in the mechanical and chemical proper- ties of the materials. Morphology of the composites can be investigated by different techniques; such as Scanning Electron Microscopy (SEM), Optical Microscopy (OP) and Transmission Electron Mi- croscopy (TEM). These techniques are efficient to locate shape, size, distribution of filler and interac- tion with the matrix. The expanded graphite has better conductivity in comparision to untreated graphite in composites. This could be due to continuous sea-weeds phase in expanded graphite where as untreated graphite has flakes like interrupted structure [28]. Fuctionaliza- tion of the filler and matrix would increase com- patibility between filler and matrix. SEM micro- graph of poly(butylene adipate co-terephthalate) (PBAT)/MWCNT-OH shows good dispersion of MWCNT in PBAT polymer which becomes more intense in acrylic acid grafted PBAT. The TEM mi- crograph of tensile fracture also supports MWCNT- OH get dispersed well where as MWCNT forms ag- glomerates on 3 wt. % loading of filler in PBAT matrix [31]. Feller et al., also explained SEM mi- crograph of acrylic acid grafted PBT with OH- functionalized graphene oxide upto 3% shows good dispersion of nanofiller [15,38].The exfoliated CNT has conductive network, assigned for the flexible continuous phase of PS matrix [47]. C-X Liu and J-W Choi noticed dispersion of CNT above 1 % cannot be investigated by TEM due to formation of opaque nanocomposite where as SEM can explain uniform dispersion of MWCNT throughout the fracture surface. SEM micrograph of polydimethylsiloxane (PDMS)/CNT upto >5 wt. % fillers showed good dispersion with consistent clusters up to 3µm [29]. Polyaniline (PANI)/CNT and polypyrrolidine (PPy)/CNT nanocomposites have CNT coated with homogeneous polymer and formed coralloid network [36]. N. G. Sahoo et.al. observed smooth lattice structure of carbon- carbon bond in TEM image of MWCNT where as some defects are seen in COOH group functionalized MWCNT due to COOH group hanged on CNT surface. The COOH group of CNT is forming ester bond with OH group of polyurethane matrix [37]. Jyoti Giri and Rameshwar Adhikari/ BIBECHANA 20 (2023) 65-75 68 Figure 1: Surface area to volume ratio A/V of a cylindrical particle of a given volume, plotted versus aspect ratio a= l/d [13,14]. Figure 2: Ideal structures of a fullerene (left) and a carbon nanotube (right) [14,19]. Figure 3: 3D structure of graphene layers in graphite [14,19]. The SEM micrograph for transverse sec- tion cut perpendicular to extrusion direction of PBT60/EEA-CB40 nanocomposite show phase or- ganization where holes and tunnels in black corre- spond to conductive phase containing carbon black and Poly(ethylene-co-ethyl Acrylate) [15]. The selective localization of carbon black (CB) was observed in morphological study of diphasic PS/PVDF/CB composite with continuous phase of PS by X. Zhao et al., [30]. The interfacial connec- tion between PS and PVDF was not clear in SEM micrograph [28]. Similar type of phase separation can also be observed in Fig. 4 with two immisible phases of PLA/PBAT/MWCNT nanocomposites. On increasing PBAT composition, CNT migrates towards PBAT phase from PLA although there is no chemical bond reported [43]. MWCNT in PLA/MWCNT composites can also increase chunks and striation in nanocomposites [42]. The MWC- NTs also increase roughness and hydrophobicity on the surface of the polymer composites which can be seen in the SEM images of polyhydroxy valerate (PHBV)/MWCNT. The micrographs of nanocom- posites of MWCNT varying from 0 %, 1 %, 1.5 % Jyoti Giri and Rameshwar Adhikari/ BIBECHANA 20 (2023) 65-75 69 Figure 4: SEM Image of PLA/PBAT/ MWCNT nanocomposite [19]. Figure 5: SEM micrographs showing fracture surface PHBV/MWCNT with (a) 0 %, (b) 1 %, (c) 1.5 % and (d) 2 of MWCNT [40]. and 2 % in PHBV show increasing roughness re- spectively as shown in Fig. 5 (a, b, c and d). The 0 % of MWCNT in nanocomposites found to have smooth surface where as MWCNT in PHBV found to have homogeneous dispersion of MWCNT in ma- trix and are incompatible to matrix resulting voids into the nanocomposites. The voids cause rough- ness and increasing with MWCNT see Fig. 5 [40]. The data is further supported by the increasing contact angle value for surface of same nanocom- posites as shown in Fig 6a. The increase of θ = 55o for pure PHBV to 87o on 1 % loading of MWCNT is a significant rise in hydrophobicity. Moreover, the smooth and rough surfaces show a similar trend and significance on rough parts of the nanocomposite surface as shown in Fig 6b [40]. 4 Mechanical performance and thermosta- bility of MWCNT-based Nanocomposites Polymers are class of materials in which one can induce or reinforce any properties such as mechan- ical, morphological or conductivity. In this re- gard, different reinforcing inorganic materials such as MWCNT alone or in combination with other ma- terials such as carbon blacks, graphenes, nanodia- monds, hydrogenated CNT etc., can be incorpo- rated into polymer materials [48, 49]. Fig.7 clearly shows the reinforcing effect of increasing wt.% of MWCNT in polycarbonate. The Young’s modu- lus is increasing with increasing concentration of MWCNT [50]. Other properties like charge barrier, and con- ducting property can be induced into the poly- mer matrix by the dispersion of conductive fillers such as CNTs or polymers intrinsically conduc- tive [38, 40, 47]. The practices of researchers are with different types of polymers molded with CNT or conducting polymer to reinforce the mechanical, thermo mechanical properties and conductivity of nanocomposites. Mixing a filler into the polymer may be a simple technique but the major challenge for the scientist is to make them compatible with the polymer. In comparison to neat filler, functionalized fillers of re- spective polarity have more good compatibility. N. G. Sahoo et al., synthesized polyurethane and in- corporated COOH-functionalized MWCNT by situ polymerization in a urethane matrix. The com- posite has good dispersion and adhesion of COOH- MWCNT on polyurethane matrix with pronounc- ing advances thermomechanical property [15]. The Jyoti Giri and Rameshwar Adhikari/ BIBECHANA 20 (2023) 65-75 70 Figure 6: (A) Photographs showing increasing hydrophobicity with increasing MWCNT in PHBV/MWCNT nanocomposites, (B) the bar diagram indicating the effect of increasing contact angle value on increasing MWCNT in PHBV [40]. electrical conductivity in PS/MWCNT composite can be reinforced by the 2 wt-% of loading CNT [47]. 5 Electrical Conductivity of MWCNT based Nanocomposites Carbon material is one of the filler with wide conducting ability. Composites of conducting filler with polymers results in conductive polymer nanocomposite which have low density, low weight, high mechanical performance, low cost and easy processability. Carbon materials carbon black, car- bon fibers, carbon nanotubes (CNTs) have conduc- tivity value (σ) ranges from 101 S/cm, 103 S/cm), CNTs are one of the most interesting materials with high strength. The sp2 hybridization of the carbon form allotropic tubular structure and these struc- ture modified to form single walled carbon nan- otubes (SWCNT), multiwalled carbon nanotubes (MWCNT), nanobud etc. Such carbon materials are conductive even in little amount and opens dif- ferent avenues of applications as composites with polymer. Therefore numerous researches are in the process throughout the world to achieve optimum best conducting polymer composites for different advance applications. MWCNT has been incor- porated into different polymers such as ethylene vinyl acetate copolymer (EVA) [28], polyurethane block [29], polystyrene (PS)/polyvinylidene fluoride (PVDF) composites [30], polyolefins [31], polyesters [18, 32] and PLA [51] In these system electrical- conducting properties, thermal, morphological, me- chanical and dielectric properties are enhanced. MWCNT also worked as compatibilizer between PS and PVDF [?]. The electrical resistivity in Fig. 8 of the PBAT, acrylic acid grafted PBAT with MWCNT and MWCNT-OH composites were measured directly on laminated films (0.1 mm thick) with an Ohm- Stat RT-1000 resistivity meter. The significant de- crease in resistivity with the addition of conduct- ing fillers MWCNT and MWCNT-OH by 1 wt-% can be seen in Fig. 8. The electrical resistivity decreases from 1×1016 Ω/sq to 1×1010 Ω/sq dif- fering by 1×106 times for PBAT/MWCNT. Simi- larly, 1 wt-% addition of MWCNT-OH in PBAT- g-AA decreases to 8×107 Ω/sq. The difference in resistivity between 1 wt-% and 3 wt-% loading of MWCNT and MWCNT-OH is 1×102 Ω/sq approx- imately. On adding 5 wt-% of filler the resistivity decreases more to 1×101 Ω/sq. Therefore upto 3 wt-% of MWCNT and MWCNT-OH sharply reduce the resistivity where as 5 and more wt-% loading of MWCNT and MWCNT-OH does not reduce in the appreciable amount. Moreover, the PBAT-g- AA/MWCNT-OH composites have more reduction in resistivity in comparison to PBAT/MWCNT. This might have happened due to the ester bond formation between arylic acid in PBAT and OH- group in MWCNT and ester bonds are always stronger than the hydrogen bond which is in be- tween PBAT and MWCNT [32]. Biodegradable conducting nanocomposites with PLA and MWCNT with increasing concentration of CNT in composite from 0 wt-% to 1.5 wt-% found Jyoti Giri and Rameshwar Adhikari/ BIBECHANA 20 (2023) 65-75 71 Figure 7: Stress-Strain curve showing reinforcement in polycarbonate by filling 2 wt-% and 5 wt-% MWCNT [50]. Figure 8: The electrical resistivity of PBAT, PBAT-g-AA, PBAT/MWCNT, and PBAT-g-AA/MWCNT- OH composites [30]. to increase crystallization, thermal degradation and at the same time reported drop in surface resistivity [41]. C.S. Wu and H.T. Liao modified poly (buty- lene terephthalate) (PBT) by surface grafting with acrylic acid and graphene oxide was modified to acid chloride (GO)-COCl) derivative. Composites of such materials have found improved thermal and decreased with graphene oxide (GO) and resistivity property and antistatic property [33]. 6 Antibacterial properties Dispersed CNT’s in nanocomposites can induce an- tibacterial properties. As carbon is inorganic filler spread throughout the matrix renders the bacte- rial growth showing by increasing hydrophobicity as mentioned above and induce antibacterial prop- erty in nanocomposites [40]. Fig. 9 (A) shows the decrease in survival of bacterial colonies on fixed loading of E. coli (0.1 mL) with respect to fixed volume and time dur- ing incubation with the PBAT-g-AA/MWCNT (3 wt-%). E. coli colonies grow on incubation, after 3 hours slowly the composite inhibits the growth of E. coli. In Fig. 8(B), 12 hours incubation al- most all colonies are disappeared [32]. The infec- tious bacterial growth of E. coli can be observed in the prepared composites of C.S. Wu. The E. coli cell count with respect to the exposure time of the composites with bacteria was given in the Fig. 8 A and B. The PBAT and PBAT-g-AA resist the growth of E.coli where as the increase in % incor- poration of MWCNT and MWCNT-OH not only decrease in growth of E.Coli but also suppress the growth of bacteria in the culture to almost zero cell count. Fig. 10 shows the survival ratio of E.coli in contact with the PBAT or PBAT-g-AA sur- face. Exposure of composite with bacteria upto 6 hours doesnot hinder the growth but after 6 hours exposure result concluded that increase in % of MWCNT and MWCNT-OH in composites started to decrease survival ratio of bacteria showing anti- bacterial effect of the composites [32]. However, en- hanced biodegradation was also observed in PBAT/ MWCNT nanocomposites compatibilized with ZnO Jyoti Giri and Rameshwar Adhikari/ BIBECHANA 20 (2023) 65-75 72 Figure 9: (A) Photographs show PBAT-g-AA/MWCNTs (3 wt. %) samples loaded with a fixed volume (0.1 mL) of E. coli. (B) E. coli was exposed to PBAT-g-AA/MWCNTs (3 wt-%) for evaluation of antibacterial activity [32] . Figure 10: Exposure survival ratio of E. coli cells during exposure to PBAT or PBAT-g-AA and its composite surfaces [32]. in more than 0.2 %, indicating bacterial degrada- tion. 7 Conclusion Carbon in different allotropic states a nanometric dimension of up to 100 nm becomes the nanofiller where the aspect ratio provides an interacting sur- face for the polymer matrix in the nanocomposite. Nanocomposite can be prepared by simple tech- niques of compounding. Filler-matrix rearrange- ment can be investigated by different spectroscopic methods like SEM, optical microscopy (OM), TEM etc., which confirms that significant reinforcement, is achieved only when filler and matrix are compat- ible with each other. The nano-carbon materials such as MWCNT, nanodiamond, and nanoscopic graphite can be used to reinforce mechanical prop- erties and thermostability and at the same time are capable of producing synergetic effects in their nanocomposites to reinforce mechanical properties, induce electrical conductivity as well as other func- tionalities in the different kinds of polymers. All such properties are boon for material science and engineering making the composites nanomaterials applicable in numerous fields in developing novel devices and technologies. Acknowledgement Jyoti Giri wants to thank Japan Science & Technol- ogy, Sakura Science Exchange Program and Profes- sor Takahiro Maruyama, Meijo University, Nagoya, Japan for strong motivation in the field of conduct- Jyoti Giri and Rameshwar Adhikari/ BIBECHANA 20 (2023) 65-75 73 ing carbon based polymer composites. References [1] Q. Wu et al. Mechanical properties of nano- materials: A review. Nanotechnology Reviews, 9:259–273, 2020. 10.1515/ntrev-2020-0021 [2] J. R. Peralta-Videa et al. Nanomaterials and the environment: A review for the biennium 2008–2010. Journal of Hazardous Materials, 186:1–15, 2011. doi:10.1016/j.jhazmat.2010.11.020 [3] L. A. Kolahalam et al. Review on nanoma- terials: Synthesis and applications. Materials Today: Proceedings, 16:1–9, 2019. doi:10.1016/j.matpr.2019.07.371 [4] M. S. Senthil Kumar et al. Effects of nano- materials on polymer composites-an expatiate view. Reviews on Advanced Materials Science, 38:40–54, 2014. [5] P. Somdee et al. Thermal analysis of polyurethane elastomers matrix with different chain extender contents for thermal conductive application. Journal of Thermal Analysis and Calorimetry, 138:1003–1010, 2019. 10.1007/s10973-019-08183-y [6] R. Chawla and S. Sharma. Molecular dynamics simulation of carbon nanotube pull-out from polyethylene matrix. Composites Science and Technology, 144:169–177, 2017. 10.1016/j.compscitech.2017.03.029 [7] S. U. M. Hashmi et al. Synthesis and charac- terization of polyvinyl chloride matrix compos- ites with modified scrap iron for advanced elec- tronic, photonic, and optical systems. Nano- materials, 12:3147, 2022. 10.3390/nano12183147 [8] R V Kurahatti et al. Defence applications of polymer nanocomposites. Def. Sci. J., 60(5):551–563, 2010. [9] A P Mouritz. Post-fire flexural properties of fibre-reinforced polyester, epoxy and phenolic composites. J. Mater. Sci., 37(7):1377–1386, 2002. 10.1023/A:1014520628915 [10] J D Megiatto Jr et al. Phenolic matrices and sisal fibers modified with hydroxy terminated polybutadiene rubber: Impact strength, wa- ter absorption, and morphological aspects of thermosets and composites. Ind. Crop. Prod., 31(2):178–184, 2010. 10.1016/j.indcrop.2009.10.001 [11] S Pradhan et al. Effect of filler dimensional- ity on mechanical properties of nanofiller re- inforced polyolefin elastomers. Polym. Sci., pages 1–9, 2013. 10.1155/2013/284504 [12] N Khadka et al. Surface modification of polyvinyl-nanocellulose composites for hy- drophobic self-cleaning solar panel cover. Macromol. Symp., 403:1–6, 2022. 10.1002/masy.202100485 [13] N G McCrum et al. Principles of polymer en- gineering. Oxford University Press, 1997. [14] S Anandhan and S Bandhopadhaya. Polymer nanocomposites: From synthesis to applica- tions. In Nanocomposites and Polymers with Analytical Methods, chapter 1, pages 1–27. In Tech, 2011. [15] J F Feller et al. Conductive polymer composites (cpcs): comparison of elec- trical properties of poly(ethylene-co-ethyl acrylate)-carbon black with poly(butylene terephthalate/poly(ethylene-co-ethyl acrylate)-carbon black. Polym. Adv. Technol., 13(10-12):714–724, 2002. 10.1002/pat.254 [16] T. Liu et al. Morphology and mechanical prop- erties of multiwalled carbon nanotubes rein- forced nylon-6 composites. Macromolecules, 37(19):7214–7222, 2004. 10.1021/ma049132t [17] Yiyuan Wang, Yixuan Zhang, Yingzhe Ma, Jie Liu, and Chuanbing Huang. Comparative study of three carbon additives: Carbon nan- otubes, graphene, and fullerene-c60, for syn- thesizing enhanced polymer nanocomposites. Nanomaterials, 10(5):838, 2020. 10.3390/nano10050838 [18] K. N. Dhakal et al. Electrically conductive and piezoresistive polymer nanocomposites us- ing multiwalled carbon nanotubes in flexi- ble copolyester: Spectroscopic, morphological, mechanical and electrical properties. Nano- Structures & Nano-Objects, 29:100806, 2022. 10/1016/j.nanoso.2021.100806 [19] C. Wang et al. Polymer containing fullerene or carbon nanotube structures. Progress in Poly- mer Science, 29(11):1079–1141, 2004. 10.1016/j.progpolymsci.2004.08.001 [20] A. C. Lopes et al. Aluminosilicate and aluminosilicate based polymer composites: Present status, applications and future trends. Progress in Surface Science, 89:239–277, 2014. 10.1016/j.progsurf.2014.08.002 https://doi.org/10.1515/ntrev-2020-0021 https://doi.org/doi:10.1016/j.jhazmat.2010.11.020 https://doi.org/doi:10.1016/j.matpr.2019.07.371 https://doi.org/10.1007/s10973-019-08183-y https://doi.org/10.1016/j.compscitech.2017.03.029 https://doi.org/10.3390/nano12183147 https://doi.org/10.1023/A:1014520628915 https://doi.org/10.1016/j.indcrop.2009.10.001 https://doi.org/10.1155/2013/284504 https://doi.org/10.1002/masy.202100485 https://doi.org/10.1002/pat.254 https://doi.org/10.1021/ma049132t https://doi.org/10.3390/nano10050838 https://doi.org/10/1016/j.nanoso.2021.100806 https://doi.org/10.1016/j.progpolymsci.2004.08.001 https://doi.org/10.1016/j.progsurf.2014.08.002 Jyoti Giri and Rameshwar Adhikari/ BIBECHANA 20 (2023) 65-75 74 [21] M. N. Norizan et al. Carbon nanotubes: Func- tionalisation and their application in chemical sensors. RSC Advances, 10(69):43704–43732, 2020. 10.1039/d0ra09438b [22] M Tebyetekerwa et al. Electrospun nanofibers- based face masks. Adv. Fiber Mater., 2:161– 166, 2020. 10.1007/s42765-020-00049-5 [23] M Radulaski et al. Nanodiamond integration with photonics devices. Laser Photonics Rev., 1800316:1–14, 2019. 10.1002/lpor.201800316 [24] R Sorrentino et al. Interlayers for non-fullerene based polymer solar cells: distinctive features and challenges. Energy Environ. Sci., 14:180– 223, 2021. 10.1039/D0EE02503H [25] A Iqbal et al. A review featuring the fun- damentals and advancements of polymer/cnt nanocomposite application in aerospace indus- try. Polym. Bull., 78:539–557, 2021. 10.1007/s00289-019-03096-0 [26] A Lagashetty and A Venkataraman. Polym nanocompos. Reson., 10:49–60, 2005. 10.1007/BF02867106 [27] VK Rangari et al. Mechanical, thermal, and electrical conducting properties of cnts/bio- degradable polymer thin films. J. Appl. Polym. Sci., 129:1249–1255, 2013. 10.1002/app.38794 [28] I Tavman et al. Preparation and charac- terization of highly electrically and thermally conductive polymeric nanocomposites. Arch. Mater. Sci. Eng., 40:84–88, 2009. [29] C-X Liu and J-W Choi. Improved dispersion of carbon nanotubes in polymers at high con- centrations. Nanomater., 2:329–347, 2012. 10.3390/nano2040329 [30] X. Zhao et al. Tuning the dielectric properties of polystyrene/poly(vinylidene fluoride) blends by selectively localizing carbon black nanopar- ticles. The Journal of Physical Chemistry B, 117(B):2505–2515, 2013. 10.1021/jp310021r [31] W Kaminsky. Metallocene based polyolefin nanocomposites. Mater., 7(3):1995–2013, 2014. 10.3390/ma7031995 [32] C. S. Wu. Antibacterial and static dissipat- ing composites of poly(butylene adipate-co- terephthalate) and multi-walled carbon nan- otubes. Carbon, 47(13):3091–3098, 2009. 10.1016/j.carbon.2009.07.023 [33] M. Shahlari and S. Lee. Mechanical and morphological properties of poly(butylene adipate-co-terephthalate) and poly(lactic acid) blended with organically modified silicate lay- ers. Polym. Eng. Sci., 52(7):1420–1428, 2012. 10.1002/pen.23082 [34] M. F. Mina et al. Characterization of biodegradable nanocomposites with poly (lac- tic acid) and multi-walled carbon nanotubes. Int. J. Chem. Nucl. Mater. Metallurg. Eng., 7:66–71, 2013. 10.5281/zenodo.1081613 [35] H. Liu et al. Application of biodegradable and biocompatible nanocomposites in electronics: Current status and future directions. Nano- mater., 9(7):950, 2019. 10.3390/nano9070950 [36] C. Peng et al. Carbon nanotube and con- ducting polymer composites for supercapaci- tors. Prog. Nat. Sci., 18(6):777–788, 2008. 10.1016/j.pnsc.2008.03.002 [37] C. S. Wu and H. T. Liao. Prepara- tion and characterization of functionalized graphite/poly(butylene terephthalate) com- posites. Polym. Bull., 72(7):1799–1816, 2015. 10.1007/s00289-015-1372-x 2015 [38] S. Hotta et al. Conducting polymer composites of soluble polythiopenes in polystyrene. Syn- thetic Metals, 22:79–87, 1987. 10.1016/0379-6779(87)90573-X [39] Y. Guan et al. A novel composite material for flexible wearable devices based on eutectic gallium indium (egain), multi-walled carbon nanotubes (mwcnts) and polydimethylsiloxane (pdms). Composite Structures, 291:115653, 2022. 10.1016/j.compstruct.2022.115653 [40] A. P. Lemes et al. Phbv/mwcnt films: hy- drophobicity, thermal and mechanical prop- erties as a function of mwcnt concentration. Journal of Composites Science, 3:1–13, 2019. 10.3390/jcs3010012 [41] S. W. Ko et al. Morphological and rheological characterization of multi-walled carbon nan- otube/pla/pbat blend nanocomposites. Poly- mer bulletin, 63:125–134, 2009. 10.1007/s00289-009-0072-9 https://doi.org/10.1039/d0ra09438b https://doi.org/10.1007/s42765-020-00049-5 10.1002/lpor.201800316 https://doi.org/10.1039/D0EE02503H https://doi.org/10.1007/s00289-019-03096-0 https://doi.org/10.1007/BF02867106 https://doi.org/10.1002/app.38794 https://doi.org/10.3390/nano2040329 https://doi.org/10.1021/jp310021r https://doi.org/10.3390/ma7031995 https://doi.org/10.1016/j.carbon.2009.07.023 https://doi.org/10.1002/pen.23082 https://doi.org/10.5281/zenodo.1081613 https://doi.org/10.3390/nano9070950 10.1016/j.pnsc.2008.03.002 https://doi.org/10.1007/s00289-015-1372-x 2015 https://doi.org/10.1016/0379-6779(87)90573-X https://doi.org/10.1016/j.compstruct.2022.115653 https://doi.org/10.3390/jcs3010012 https://doi.org/10.1007/s00289-009-0072-9 Jyoti Giri and Rameshwar Adhikari/ BIBECHANA 20 (2023) 65-75 75 [42] N. Grossiord et al.. High-conductivity polymer nanocomposites obtained by tailoring the char- acteristics of carbon nanotube fillers. Advanced Functional Materials, 18:3226–3234, 2008. 10.1002/adfm.200800528 [43] M Shahlari and S Lee. Mechanical and mor- phological properties of poly(butylene adipate- co-terephthalate) and poly(lactic acid) blended with organically modified silicate layers. Poly- mer Engineering & Science, 52:1–9, 2012. 10.1002/pen.23082 [44] Md. K. H. Bhuiyan et al. Crystalline morphol- ogy and properties of multi-walled carbon nan- otube filled isotactic polypropylene nanocom- posites: Influence of filler size and loading. Composites Part A: Applied Science and Man- ufacturing, 52:70–79, 2013. 10.1016/j.compositesa.2013.05.011 [45] S. W. Ko et al. Morphological and rheological characterization of multi-walled carbon nan- otube/pla/pbat blend nanocomposites. Poly- mer Bulletin, 63:125–134, 2009. 10.1007/s00289-009-0072-9 [46] N. G. Sahoo et al. Synthesis of polyurethane nanocomposites of functionalized carbon nan- otubes by in-situ polymerization methods. Journal of the Korean Physical Society, 51:1– 6, 2007. 10.3938/jkps.51.1 [47] K. D. Behler et al. Nanodiamond-polymer composite fibers and coatings. ACS nano, 3(2):363–369, 2009. 10.1021/nn800445z [48] L.W. Zhang et al. Mechanical properties of diamond nanothread reinforced polymer com- posites. Carbon, pages 1–23, 2018. 10.1016/j.carbon.2018.02.053 [49] A. Eitan et al. Reinforcement mechanisms in mwcnt-filled polycarbonate. Composites Sci- ence and Technology, 66(9):1162–1173, 2006. 10.1016/j.compscitech.2005.10.004 [50] R. Amir et al. Graphene induced microstruc- tural changes of pla/mwcnt biodegradable nanocomposites: rheological, morphological, thermal and electrical properties. RSC Ad- vances, 6:49747–49759, 2016. 10.1039/C6RA08345E [51] FF.-F. Ge et al., Barrier performance and biodegradability of antibacterial poly(butylene adipate-co-terephthalate) nanocomposites re- inforced with a new mwcnt-zno nanomaterial. Nanotechnology, 32(48):485706, 2021. 10.1088/1361-6528/ac1b52 https://doi.org/10.1002/adfm.200800528 https://doi.org/10.1002/pen.23082 https://doi.org/10.1016/j.compositesa.2013.05.011 https://doi.org/10.1007/s00289-009-0072-9 https://doi.org/10.3938/jkps.51.1 https://doi.org/10.1021/nn800445z https://doi.org/10.1016/j.carbon.2018.02.053 10.1016/j.compscitech.2005.10.004 https://doi.org/10.1039/C6RA08345E https://doi.org/10.1088/1361-6528/ac1b52 Introduction Preparation of conducting polymer nanocomposites Solution casting in-situ polymerization Internal melt mixing Twin screw extruder Morphological Features of MWCNT-based Nanocomposites Mechanical performance and thermostability of MWCNT-based Nanocomposites Electrical Conductivity of MWCNT based Nanocomposites Antibacterial properties Conclusion