Study On The Compatibilization Of The Butyl-Rubber/Nylon Thermoplastic Elastomer

Butyl rubber/nylon thermoplastic elastomer, with the excellent properties of both the butyl rubber and nylon, such as good air tightness, elasticity, thermal plasticity and recycling performance, is a kind of "green" chemical new materials, which lead to it's great application prospect in the tyre airtight lining layer, refrigerator air hose and so on. However, the poor compatibility of both increases the difficulty of its preparation seriously, and makes it hard to obtain fine microscopic morphology and good comprehensive performance of the butyl rubber/nylon thermoplastic elastomer. In past studies, using maleic anhydride grafted polymer increase the capacity between butyl rubber and nylon usually, while the compatibilizing effectiveness is not ideal, and the poor performance of the compatibilizers themselves have a disadvantageous effect on the properties of butyl rubber/nylon thermoplastic elastomer.This topic usinga block oligomer (PAG) comprised with alpha methyl styrene (AMS) and GMA and modified butyl rubber tocompatibilize the butyl rubber/nylon system. Epoxy group will begrafted on the butyl rubber which is able to react with the amino group of nylon 12 (PA 12) rapidly, so as to realize the reactive capacity increasing. This method of compatibilization don't introduce a third phase as the compatibilizers, which will have no effect on the performance of the thermoplastic elastomer material as the reasons mentioned above. Therefore, the main research in the subject is to modify butyl rubber (IIR) and brominated butyl rubber (BUR) with glycidyl methacrylate (GMA) by melting method and study the influencing factors of grafting degree. Also, we study the compatibilizing effectiveness of the too method. The conclusion is as follows:1?PAG can lead to the crosslinking of PA 12, result in unideal compatibilizing effect to the system of IIR and PA 12.2?Chemical titration method can be used in the determination of the grafting rate of GMA. The modified butyl rubber has the higher grafting rate at the higher temperature (220 ?), as the polymerization of GMA is the main factor to reduce graft rate during grafting reaction process that will be suppressed at high temperature. We prepared modified butyl rubber with grafting ratio of 0.92% by adding styrene (St) as a co-monomer, which can improve the grafting rate obviously. We also find that, no matter a single monomer modification method or co-monomer modification method, the grafting rate is unchanged or even decreases after increasing first with the increase of the dosage of the GMA and dicumyl peroxide (DCP) as the free radical initiator. The reason is that the polymerization of the GMA become more seriously with the higher concentration of GMA and DCP, which will go against graft reactive.3?B?R will be cross-linked seriously during grafting process, which can be suppressed with the method that lower the reaction temperature (170 ?) and reduce the dosage of DCP, while can not be avoided completely. Fortunately, we can judgment qualitative that the GMA grafting rate of modified BUR is higher than the grafting rate of modified ?R at the same formula and process conditions by Fourier infrared characterization.4?The ?R-g-GMA without purification contains GMA oligomer, which can lead to the crosslinking of PA 12 just like PAG dose. That makes the system viscosity inhomogeneous and adverse to the two phase dispersion. The higher of grafting rate and the higher dosage of pre-purification ?R-g - GMA, the better the micro morphology of the blends is. It's because both that can reduce the interfacial tension of ?R and PA with the graft copolymer reacted between ?R-g-GMA and PA 12, which is advantageous to the dispersion of ?R. Finally, we decrease the size of the dispersed particle of ?R from 1-5 um to less than 1 um by using ?R-g-GMA as the compatibilizer in the preparation of ?R/PA12 alloy.5?B?R-g-GMA has better compatibilizing effect prepared under 170 ? than prepared under 220 ? on the B?R/PA12 blends. The higher reactivity between B?R and GMA makes the grafting rate higher and suppress the polymerization of GMA, which makes the B?R-g-GMA without purification also can play a role in increasing the capacity, although its effect is weaker than the one after purification. Similarly, the higher dosage of B?R-g-GMA as compatilizer will achieve a more fine phase. We decrease the size of the dispersed particle of B?R from 1-3 um to 0.4 um by using 20phr B?R-g-GMA as the compatibilizer in the preparation of ?R/PA12 alloy, and decrease the size of the dispersed particle of B?R from 2-5 um to 2 um by using 10phr B?R-g-GMA in the preparation of ?R/PA12TPV, whichalso improved the mechanical properties of TPV obviously.