Morphology, mechanical and thermal properties of nano-structured full IPNs based on polyisoprene and PMMA

John, Jacob; Suriyakala, R.; Thomas, Selvin P.; Méndez, J M; Pius, Anitha; Thomas, Sabu

doi:10.1007/s10853-010-4280-3

Cited by 13 publications

(15 citation statements)

References 17 publications

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“…Even though a high temperature transition is not present, the influence of PMMA can be seen in the inward shift of the transition and the decreased slope along with an increase in overall storage modulus. Here the crosslinking of the second component enhanced the interpenetration of rigid PMMA chains more effectively into the entangled NR network, indicating that some degree of enforced miscibility was obtained via IPN synthesis . The SEM analysis showed that the system possesses a sea‐island morphology with very small PMMA domains scattered all over the NR matrix .…”

Section: Resultsmentioning

confidence: 83%

“…Here the crosslinking of the second component enhanced the interpenetration of rigid PMMA chains more effectively into the entangled NR network, indicating that some degree of enforced miscibility was obtained via IPN synthesis . The SEM analysis showed that the system possesses a sea‐island morphology with very small PMMA domains scattered all over the NR matrix . The inward shift in transition is also a proof of some degree of molecular level mixing achieved during IPN formation.…”

Section: Resultsmentioning

confidence: 99%

“…Morphology, mechanical properties, thermal stability and gas transport behaviour of full IPNs based on NR and PMMA have been investigated using various techniques . The crosslinking level of the two phases facilitates deeper interpenetration between the networks and has noticeable effects on the compatibility of immiscible components during IPN formation.…”

Section: Introductionmentioning

confidence: 99%

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Relaxations and chain dynamics of sequential full interpenetrating polymer networks based on natural rubber and poly(methyl methacrylate)

et al. 2013

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The relaxations of natural rubber (NR)/poly(methyl methacrylate) (PMMA) interpenetrating polymer networks (IPNs) were studied using dynamic mechanical analysis, electron spin resonance (ESR) and solid state NMR spectroscopy. Samples with a lower concentration of PMMA in IPNs (25 wt%) showed only one relaxation, which corresponds to NR with a slight shift to higher temperature. IPNs with 35 wt% of PMMA showed very broad transitions arising from βand α-relaxations in PMMA, with the β-relaxation slightly shifted to lower temperature. These compositions also showed a higher modulus at all temperatures. Highly phase separated IPNs showed a complete drop of modulus at 423 K. Higher crosslinking in the NR phase increases the miscibility and decreases the temperature difference between transitions, while in PMMA it increases the phase separation and does not affect the β-relaxation of the PMMA chains. The ESR results showed that PMMA chains located in the PMMA-rich and NR-rich domains have different motional characteristics. The strong interaction between PMMA and NR chains was also observed by carbonyl relaxation in solid state NMR spectra. It was found that medium level crosslinking is needed for better interpenetration between phases. EXPERIMENTAL MaterialsHigh molecular weight NR (M w ≈ 500 000-900 000) was supplied by Rubber Research Institute of India, Kottayam, Kerala. Dicumyl peroxide (99%), the crosslinker for NR, was purchased from Aldrich and used as received. Methyl methacrylate (MMA, Aldrich) and ethylene glycol dimethylacrylate (EGDMA, Aldrich), the crosslinker for MMA, were distilled under vacuum prior to use. Azobisisobutyronitrile (AIBN, Aldrich), the initiator for MMA polymerization, was purified by recrystallization from methanol. Preparation of IPNsSheets of crosslinked NR (1-2 mm thick) were weighed and kept immersed in a homogeneous mixture of MMA, EGDMA and AIBN (0.7 g per 100 g of MMA). The NR sheets were swollen for various time intervals to obtain different weight percentages of PMMA. The swollen samples were kept for a few hours at 273 K to achieve an equilibrium distribution of the MMA monomer in the matrix. These swollen networks were heated at 353 K for 6 h and at 373 K for 2 h in an atmosphere of MMA to complete the polymerization and crosslinking of MMA. Four IPN samples were made with the following ratios of NR and PMMA: 75:25 (NIM 25 ), 65:35 (NIM 35 ), 50:50 (NIM 50 ) and 40:60 (NIM 60 ). Concentrations of crosslinker in weight percentage per 100 g for the NR and PMMA phases are denoted as superscripts before ( x ) and after ( y ) the sample's symbol, respectively. Thus, a general symbol for all the IPN samples is x NIM y z where x stands for wt% of crosslinker for the NR phase, y stands for wt% of crosslinker for the PMMA phase and z stands for wt% of the PMMA phase in the IPN sample. The obtained IPNs were kept in vacuum to eliminate residual unreacted MMA. The composition of the IPN samples was determined on wileyonlinelibrary.com

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Section: Resultsmentioning

confidence: 83%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Relaxations and chain dynamics of sequential full interpenetrating polymer networks based on natural rubber and poly(methyl methacrylate)

et al. 2013

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“…Mechanical properties of the IPNs based on PI/PMMA were correlated to the morphology of the system [81]. Tensile strength of the IPN samples are plotted as a function of the overall PMMA content as shown in Figure 7.39.…”

Section: With Permission From American Chemical Societymentioning

confidence: 99%

“…40 TEM image of IPN s with nanometre-sized morphology[81]. 41 ESR spectra of probe measured as a function of temperature in semi IPN based on PI and PMMA with 50/50 composition[81].…”

mentioning

confidence: 99%