Synthesis, Structure Property Characterization Of Multi Functionalization Isotactic Polypropylene And Primary Research Of Its Post Functionalization Reactivity

The present work is concerned with the isotactic polypropylene (iPP) multi-functionalization with glycidyl methacrylate (GMA) by in-situ chlorinating graft copolymerization (ISCGC). For the sake of clarity, the multi functionalized iPP obtained from this system will be named as PP-cg-GMA. ISCGC create a novel and convenient grafting modification approach, in which chlorine act as free radical initiator as well as radical terminate agent. The transfer and coupling reaction of macroradicals can be effective limited due to the timely termination effect of chlorine, which result in the synthesized functioned PP with very controlled degradation and no gelation. GMA is used as grafted monomer because of its unique allyl-containing structure. The allyl hydrogen can be substituted by chlorine radical due to the high activity of chlorine and the formation of allyl radical made it possible to synthesize multi functionalized iPP. Multi functionalized iPP with both reactivity epoxy groups as well as C=C double bonds located at its graft side chain is obtained if the allyl radical or PGMA radicals containing double bond located at the terminal of its molecular chain combination with PP macroradicals. Additionally,there's also trace chlorine atoms in the structure of PP-cg-GMA.The main target of this work is to synthesize multi functionalized iPP with higher grafting level, very controlled chain degradation. In addition, we will do a preliminary study of the reactivity of epoxy groups. Firstly, the reaction conditions including the addition methods of GMA monomers, reaction temperature, GMA initial content, chlorine concentration and the addition of a second comonomer (styrene) would be explored to discuss the influence of reaction conditions on grafting degree. The presence of epoxy and C=C doubles bonds that located in the grafted side chains are analyzed by FTIR and 1HNMR. In order to check the capability of this system to control the iPP degradation, both the number average molecular weight (Mn) and viscosity average molecular weight (Mv) are used to investigate the iPP chain scission. Gel content was used to characterize the coupling reaction. According to the detailed structure characterization,we try to rationalize the complex mechanism of this process.Secondly, for the purpose of further discussing the effect of GMA side chains on the property of iPP, DSC, POM and TGA are performed to investigate the crystallization and thermal property of functionalized iPP respectively. What's more, DMA was used to investigate the glass transition temperature (Tg) and stiffness of PP-cg-GMA and the static mechanical test (tensile test, impact test) was carried out to explore the effect of graft side chains on the mechanical properties of polymer samples.Lastly, primary researches of epoxy reactivity with carboxylate, hydroxyl and amine group are conducted. Moreover, PP-cg-GMA and nitrile rubber with terminal hydroxyl groups (HTBN) can undergo reaction to synthesize the polymer reactivity compatible system, and elevate the toughness of iPP samples. The possibility of its reactivity is determined by FTIR. The compatibilization of PP-cg-GMA and HTBN was discussed by DMA.