untitled ISSN 2 Tensile epoxy r Widad Sal 1 Chemistry Dep 2 Chemistry Dep * Corresponding Tel.: +964.780.1 ARTICLE IN DOI: 10.5155/e Received: 18 M Received in rev Accepted: 25 Ju Published onlin Printed: 30 Sep KEYWORDS DMA Epoxy resin Polysulphide Impact strength Tensile strength IPNs preparatio Interpenetratin 1. Introduct Thermos thermoplasti temperature result in the and especial of thermose achieved by example, th improves th improved m enhancemen toughening, polymer net extend the ra of applicatio As first composition networks he entanglemen sequential IP then swollen 2153‐2249 (Prin strength esin‐poly lih Hanoosh partment, College of partment, College of g author at: Chemis 1032793. Fax: +964 FORMATION eurjchem.7.3.352- ay 2016 vised form: 15 July uly 2016 ne: 30 September 2 ptember 2016   S h h on ng polymer networ tion setting polymer ic polymers s e, good solvent r ir use in a wid lly application etting polymers modifying the he addition o e rigidity of th mechanical pr nt can be achi blending of th tworks (IPNs), ange of propert n of the produc proposed by S of two or m ld together exc nt. IPNs can for PNs is one whe n with a seco E nt) / ISSN 2153‐ h Euro and dyna ysulphide h 1,* and Hind f Science, University f Science, University stry Department, C 4.780.1032793. E‐m -356.1459 2016 2016 rks rs have numbe such as, eleva resistance and de range of com [1]. Optimizati s for specific a structure of th f the aromat he polymer bac roperties [2,3 ieved by rubb hermoset to fo it is an entire ties and hence cts. Sperling et al. more chemical clusively by the rmed by one of ere the first net ond crosslinkin uropean Journal Europ 2257 (Online)  http://dx.doi.org/1 pean Jo Journal we amic mech elastome d Mahde Sal ty of Basra, Basra, 6 ty of Misan, Misan, 6 College of Science, U mail address: whida ABSTRACT The toughnes investigated. S weight percen analysis techn lower than gla increase with Cite this: Eur. r of advantages ated heat disto high modulus, w mmodity, engine on of the prop application has e monomer un tic structure w ckbone and lea 3]. Other pro er or thermop orm interpenet ly different rou increase the nu [4], IPNs are i ly distinct po ir permanent m two methods, twork is forme ng system, wh l of Chemistry 7 pean Journal of C 2016 Atlanta Pub 10.5155/eurjchem ournal ebpage: www hanical an er leh 2 61001, Iraq 62001, Iraq University of Basra, adhanoosh@yahoo. ss of diglycidyl Several interpen ntage of polysulp nique. From the ass transition te increasing perce J. Chem. 2016, 7 s over ortion which eering perties been it. For which ads to operty plastic rating ute to umber deally lymer mutual first a ed and ich is poly whi typ com betw oth in t obs poly fact exp com slow plas the Evid resi wid adh [7,8 (3) (2016) 352‐ Chemistry blishing House LL m.7.3.352-356.14 of Che w.eurjchem.co nalysis of Basra, 61001, Iraq .com (W.S. Hanoosh ether of bisph netrating polyme phide were prep result, the glas emperature of e entage of polysu 7(3), 352‐356 ymerized. The ich the two com e that is investi There are a mplication in t ween the comp er component the study of e served an intera yester and dia tor, the rate pected to be red mponent. Some times in wly than the s sticizer to the c second comp dence for this in are a major dely used as bin hesives and coa 8]. ‐356 LC ‐ All rights rese 459 emistry om f new IPN q. h). henol, an epoxy er networks bas pared and charac s transition tem epoxy alone and ulphide. second type i mponents are p igated in the pr number of f that curing of ponent of one may accelerate poxy resin‐pol action between amine curative of reaction of ducing due to th n an IPNs the second compon cure of the latt ponent and fu has been repo class of therm nder for fiber re ating as well as erved ‐ Printed in y s based o y resin with po ed on epoxy res cterized by dyna mperature of the d also the impa is the simultan polymerized tog esent study. factors that c f IPNs, first t network and th e the reaction. A lyester IPNs, D n the cobalt salt for the epoxy f one compon he dilution effe first componen nent, the forme er, allowing fas ll cure withou orted by Lin et mosetting polym einforced compo s other enginee n the USA n olysulphide was sin and different amic mechanical ese systems was act strength was neones IPNs in gether, and this ould leads to the interaction he initiators of As an example, Dean et al. [5], t catalyst of the y resin. Second nent might be ect by the other nt reacts more er may acts as ster reaction of ut verification. t al. [6]. Epoxy mers which are osite materials, ering materials s t l s s n s o n f , , e d e r e s f . y e , s Hanoosh and Saleh / European Journal of Chemistry 7 (3) (2016) 352‐356 353 Table 1. The quantities of the reactant used in the preparation of IPNs. First component (Polysulphide) Second component (Epoxy resin) Polysulphide % Polysulphide content (g) MnO2 content (g) Epoxy resin content (g) TETA content (g) 0 (epoxy alone ) 0.00 0.000 3.00 1.00 10 0.30 0.006 2.70 0.90 20 0.60 0.012 2.40 0.80 30 0.90 0.018 2.10 0.70 40 1.20 0.024 1.80 0.60 50 1.50 0.030 1.50 0.50 Figure 1. Chemical structure of bisphenol A diglycidyl ether (Epoxy resin). But when being cured, epoxy resin typically possess a high crosslink density which leads to a low ductility and poor fracture toughness and low impact resistance, so many efforts have made to improve the toughness of cured epoxy resin [9‐ 11]. Also, the toughness of epoxy will be improve by introduce some polymers in their network of the epoxy resin which leads to increase flexibility of the final network structure [12‐14]. On the other hand, polysulphide are widely used as flexible sealants for joints, building, sewage pipes and road surfacing [15,16], also polysulphide show a number of remarkable properties like rapid curing at ambient temperature, good adhesion on many materials high impact resistance and chemically resistance to a number of dilute acids, alkalies and organic solvents. The main objective of the present work is to synthesis of simultaneous IPNs formed from epoxy resin and liquid polysulphide in order to improve the toughness of the epoxy resin and study the effect of polysulphide on the glass transition temperature of epoxy resin. 2. Experimental 2.1. Materials The epoxy oligomer was bisphenol A diglycidyl ether (DGEPA) (Figure 1) (n = 1.5, number of repeating units; type Araldite GY‐9708‐1) supplied by Ciba Geigy Company and was reported to have an average equivalent weight of 190 g/mol. This epoxy resin was cured with stoichiometric amount of amine curing agent (Triethylenetetraamine, TETA). While the liquid polysulphide used in this study, the mercaptan terminated (SH), having the formula (HS‐CH2CH2‐ O‐CH2O‐CH2CH2‐(S‐S‐CH2CH2‐)n‐SH) was supplied from AkzoNobel, Giza, Egypt. With the following specification, viscosity was 35,000 cps at 25 °C, density 1.404 g/cm3, molecular weight was 1000 g/mol, SH‐content 1.75%, average viscosity 25 °C was 1.15 Pa.s, and trichloropropane cross‐link agent 2%, this polysulphide was cured by commercial grade MnO2. 2.2. Instrumentations Dynamic mechanical measurement were made on dynamic mechanical analyzer 6100 (DMA) by Seiko Instrument were used to estimate the glass transition temperature (Tg) of the prepared IPNs and also to estimate the storage modulus (E’) and loss modulus (E’’). The tensile strength was determined by using dumb‐bell shaped specimen conforming to ASTM‐D412 with the instrument universal testing machine Instron‐5582 (100KN), Model 122 (Canada). Izod impact strength was determined by using a ZWICK model impact tester type machine (5120), equipped with hammer (Zwick Co., Germany). Differential scanning calorimetry (DSC) model Q 20 TA was used to study the thermal behavior of these polymers by using inert atmosphere this instruments presence in Misan University, Scientific College, Chemistry Department, Misan, Iraq. Flexural strength was performed by using Tinus Olenutm fitted with three point binding fixture at cross‐head of 5 mm/min and the test was done according to ASTM D 790. Izode impact strength was determined by using Zwick model impact tester type machine (5102), equipped with a hummer (Zwick Co. Germany) and the specimens were conforming according to ASTM (D256). These two instruments presence in the Basra University, Scientific College, Chemistry Department, Basrah, Iraq. 2.3. Synthesis 2.3.1. Synthesis of IPNs The IPNs consider in this study based on epoxy resin and polysulphide were prepared by efficient mixing of different quantities show in Table 1, for a period of 2 min at room temperature, then crosslinking agents (MnO2) and tetra‐ ethylenetriamine (TETA), were added and mixed gently in order to homogenize. The samples were left overnight for curing at room temperature, then at 100 °C for 6 hr, and finally 4‐5 hr post cure at 130 °C. 3. Result and discussion 3.1. Synthesis The epoxy resin used in this study was cured by aliphatic amine, the polymerization sequence illustrated in Scheme 1. Epoxy resins are converted into 3‐dimensional networks held together by covalent bonds as a result of crosslinking reaction. This conversion of liquid or friable brittle solids into tough cross‐linked polymer is called curing and achieved by the addition of curing agent which serves as initiators for resin homo‐polymerization. While polysulphide oligomers have no workable applications in their liquid state so they are further polymerized or cured to higher molecular weight elastomers, so the curing process involves the addition of an oxidizing agent (MnO2), which allows the terminal thiol groups to form disulphide bridges. The general oxidation process can be shown in Scheme 2. On the other hand, polysulphide also react with epoxy resin through the ‐SH group leading to opining of the oxirane ring [17,18], as shown in Scheme 3. 354 Hanoosh and Saleh / European Journal of Chemistry 7 (3) (2016) 352‐356 Table 2. Effect of polysulphide content on the tensile properties of epoxy resin. Polysulphide (%) E (GPa) Tensile strength (MPa) Elongation at break (%) 0 (Epoxy alone) 2.32 29.72 3.46 10 2.13 27.31 5.10 20 2.01 26.63 6.31 30 1.83 25.01 8.76 40 1.68 23.12 14.96 50 1.13 22.01 18.45 Scheme 1 Scheme 2 Scheme 3 The characteristic bands display a strong broad band in the 3600‐3200 cm‐1 region assigned to O‐H stretching vibrations in the FT‐IR spectrum of uncured epoxy. A strong bands at 1605, 1580, 1510 and 1455 cm‐1 are assigned for Ar‐ C=C‐H stretching vibrations. Bands at 729 and 693 cm‐1 may be attributed to out of plan bending of aromatic rings. Also bands at 912 and 1042 cm‐1 due to epoxy ring, which is disappear after curing with amine. The absorption bands at 672 cm‐1 and 558.5 cm‐1 in the FT‐IR spectrum of epoxy/ polysulphide IPNs can be ascribed to C‐S group and S‐S group of polysulphide.Also the absorption band at 1428 cm‐1 is due to formation of ‐S‐CH2 linkage between ‐SH group of poly‐ sulphide and epoxide group of DGEPA. On the other hand , the broad absorption band at 3450 cm‐1 might indicated the OH group formed due to reaction between the ‐SH group of polysulphide and epoxide group. 3.2. Mechanical properties 3.2.1. Tensile behavior The load‐elongation properties were obtained using an axial extensometer coupled to a mechanical tester. All tests were performed at room temperature according to ASTM D638 method. The results showed in Table 2, and the value of tensile strength a while the elongation increases. On the other hand, as expected, the tensile modulus gradually decreases due to increase the flexibility of the formulation samples. 3.2.2. Izod impact strength Izod impact strength was evaluated using notched specimen. The rectangular specimens of 80×10×4 mm were taken according to ASTM D‐256‐88. The tests were carried out at room temperature and the values were taken from an average of at least five specimens. The Izod impact values are calculated with the Equation 1. Is (1) where, u1: the impact energy (KJ); u2: the residual energy (KJ); w: the specimen width (m); and a: the notch length (m). The impact strength results for the prepared IPNs have been summarized in Table 3. The results shown that the impact value was increase with increasing percentage of polysulphide due to the increasing toughness and elastic behavior of prepared IPNs. So, there are several methods used to improve the toughness of epoxy resin [19,20]. 3.3.3. Dynamic mechanical analysis (DMA) (Viscoelasticity data) DMA was performed and evaluated using as sample of approximately 50 mm (L) × 10 mm (w) × 1.5 mm (t) under bending mode and the data were obtained at 1 Hz on at temperature from 25 to 130 °C, at heating rate 5 °C/min. Table 3. Impac Polysulphide % 0 (Epoxy alone 10 20 30 40 50 Table 4. Storag Temperature 40 60 80 100 Table 5. The lo Temperature 40 60 80 100 The prop modulus (E’) function of t in Figures 2‐ Figure 2. Inset temperature fo Figure 3. Inset temperature fo Figure 4. Inset temperature fo ct strength value of % ) ge modulus E’ (GPa (°C) oss modulus E’’(GP (°C) perties obtaine ), loss modulus temperature. Th 6, from the dat t of storage (E’) an r IPNs containing t of storage (E’) an r IPNs containing 2 t of storage (E’) an r IPNs containing 3 Hanoosh and Sa f the prepared IPN a) data of the prepa Polysulphide (% 0 (Epoxy alone) 16.101 13.911 6.322 1.213 a) data of the prep Polysulphide (% 0 (Epoxy alone) 1.657 1.283 0.352 0.052 ed from these (E’’) and tan δ he result was o a on Table 4 an nd loss modulus ( 10% polysulphide nd loss modulus ( 20% polysulphide nd loss modulus ( 30% polysulphide aleh / European J s. ared IPNs. %) ) pared IPNs. %) ) analysis are st that is recorde obtained and sh nd 5. E’’) curves as func . E’’) curves as func . E’’) curves as func . Journal of Chem 10 13.780 3.939 0.132 0.057 10 1.052 0.812 0.089 0.004 torage ed as a howed ction of ction of ction of Figu temp Figu temp and sam dev and ratu tan stor tran in epo max with (Ta the mor istry 7 (3) (2016 Impact stren 9.32 10.73 12.04 14.21 15.11 18.33 20 6.496 0.864 0.105 0.032 20 0.948 0.539 0.047 0.003 ure 5. Inset of stor perature for IPNs c ure 6. Inset of stor perature for IPNs c There is drop d also with incr me behavior in viation occurred d 20% polysulp ure and then d δ as the ratio o rage modulus i nsition. It is sen polymer. The oxy‐polysulphid ximum [21], an h increasing p able 6). It can be temperature o re elastic behav 6) 352‐356 ngth (Kj/m2) 30 2.438 0.163 0.030 0.027 30 0.857 0.107 0.012 0.001 rage (E’) and loss containing 40% po rage (E’) and loss containing 50% po p in the storage reasing percent the case of los d at temperatu phide, the value decrease Figure of the dynamic s related to the nsitive to all m glass transitio de IPNs is de nd the result s olysulphide we e resulted from of tan delta an viour. 40 0.992 0.111 0.023 0.012 40 0.544 0.056 0.006 0.001 modulus (E’’) cur olysulphide modulus (E’’) cur olysulphide. e modulus wit tage of polysul ss modulus, but ure of 60 °C in e of E’ increase es 2‐6. The dam c loss modulus t e molecular mo olecular movem on temperatur etermined by shown that the eight percent i m the figures th nd this was att 355 50 0.206 0.035 0.017 0.022 50 0.142 0.018 0.003 0.001 rves as function of rves as function of th temperature lphide, also the t there is some the case of 10 e at this tempe‐ mping property to the dynamic otion and phase ment occurring re (Tg) of the the tan delta e Tg decreased in composition e decreasing of tributed to the f f e e e 0 ‐ y c e g e a d n f e 356 Hanoosh and Saleh / European Journal of Chemistry 7 (3) (2016) 352‐356 Table 6. Tg of prepared IPNs at different percentage of polysulphide. Polysulphide (%) Glass transition temperature (°C) 0 (Epoxy alone) 86 10 71 20 67 30 55 40 49 50 36 4. Conclusions IPNs were prepared in this study by variation percentage of polysulphide in the presence of epoxy resin, after complete curing the final product was evaluated by some mechanical properties. The result shown that the properties of epoxy resin was improved by introducing polysulphide in there structure network due to increase flexibility, also glass transition temperature was decrease through the addition of poly‐ sulphide. Acknowledgements The authors would like to thank Anis Abdol Wahab Al‐ Najar for more support, and also gratefully acknowledged to Moayd Naim Galaf and Ali Kareem Al‐Lami for the mechanical and thermal analysis, respectively. References [1]. Lee, H.; Neville, K. Handbook of epoxy resine, New York, McGraw‐Hill, 1967. [2]. Troev, K.; Grancharov, G.; Tsevi, R.; Tsekova, A. Polymer 2000, 41(19), 7017‐7022. [3]. Li, J. Polymer Bull. 2006, 56(4), 377‐384. [4]. Spering, L. H.; Mishra, V. Polym. Adv. Technol. 1995, 7(4), 197‐208. [5]. Dean, K.; Cook, W.; Zipper, M.; Burchill, P. Polymer, 2001, 42(4), 1345‐1359. [6]. Lin, M. S.; Chang, R. J. J. Appl. Polymer Sci. 1992, 46(5), 815‐827. [7]. Sarathi, R.; Sahu, R. K.; Rajeshkumar, P. Mater. Sci. Eng. 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