Design And Synthesis Of Weak Bond-containing Styrene Derivatives Monomers And Its Polymers And Their Applications In Rubber

Monomeric and polymeric compounds with weak bond structures could produce radicals when heated. Therefore, these compounds have been widely reported to serve as thermal radical initiators and modifying agent for carbon materials. The design of analogous monomers and polymers with weak bond structures was of great significance to synthesize a variety of sophisticated polymers and functionalize polymer materials. Compared with in-chain and end-chain weak bond functionalized polymer, introducing weak bond into polymer side chain has many advantages include precisely controlling the quantity and position of weak bond in polymer chain. Meanwhile, the obtained polymer can be used as backbone chain for graft copolymer and dendrimer as well as to introduce other functions. In this thesis, we analyzed and studied the thermal decomposition characteristic and initiation mechanism for many model compounds. Based on this study,we developed three new functionalized styrene monomers that containing a weak bond structure. Then polymers with weak bond structures on side chain were prepared through anionic polymerization of functionalized styrene. These polymers are interesting as stable intermediates to synthesize other sophisticated polymers and functionalize polymer materials. In addition, functionalized styrene-butadiene rubbers with a weak bond pendant were synthesized by copolymering with functionalized styrene.The functionalized styrene-butadiene rubber can be grafted onto the surface of carbon materials such as carbon black and graphene. Using this functionalized rubber, I designed and made highly dispersed, strong interfacial functionalized elastomer nanocomposites,explored the action mechanisms between weak bond structures and fillers.Follows are main results:(1) Design and synthesis of styrene monomers with a weak bond on the side chain. After analyzing the structure and bond dissociation energy of 1,1,2-triphenylethane (TPE), we synthesized two compound,1,1,1,2-tetraphenylethane (TEPE) and N,N-diphenylbenzylamine (DPBA).TEPE and DPBA have the similar structure with TPE. As model compound and initiator, the radical polymerizations of methyl methacrylate (MMA) initiated by TEPE and DPBA were researched. The thermal decomposition experiment of TEPE and DPBA are also researched by TEMPO. It is found that thermal treatment of TEPE/DPBA above 85 ℃ could produce a reactive benzyl radical and a stable triphenyl-methyl/ diphenyl-amine radical. The MMA could be successfully initiated by TEPE and DPBA above 85 ℃. Based on the above research, C-C double bond was introduced into TPE, TEPE and DPBA, respectively. Therefore, three new styrene derivatives,4-( 1,1 -diphenylethyl)styrene (DPES), 4-( 1,1,1 -tetraphenylethyl)styrene(TPES) were synthesized and 4-(N,N-diphenylamino)methylstyrene(DPAMS).(2) Prepared polymers consist of styrene derivatives with weak bond on the side chain. Polymers with weak bond on the side chain was prepared by the anionic polymerization of DPES, DPAMS and TPES. To determine the characteristics of polymerization, the anionic polymerizations of DPES, TPES and DPAMS were attempted under various polymerization conditions. It was proved that a cyclohexane/THF mixed solvent was discovered to be particularly active for anionic polymerization of DPES. Because of the bad solubility of TPES in solvents, the anionic polymerization processes of TPES was not well-controlled. PDPAMS with controlled molecular weight was obtained by living anionic polymerization of DPAMS in THF at -78 ℃. Thermal treatment of PDPES, PTPES and PDPAMS as macroinitiators in the presence of vinyl monomers effectively yield graft copolymer with different structure, such as PMMA-g-PDPES and hypergrafted PDPAMS.The polymerization of vinyl monomers initiated by polymers with weak bond pendant paovides a new way to synthesis of graft copolymer.(3) Synthesis and application of solution polymerized styrene-butadiene rubber (SSBR) with weak C-C bond on the side chain.SSBR with TPE structure (SBDR) on the side chain was synthesized by copolymerizing styrene, butadiene and DPES. After thermal treatment of SBDR with carbon black (CB) in toluene at 100 ℃, SBDR can be grafted on the surface of CB surface. The dispersion of CB in SBDR can be improved by increasing the content of DPES in SBDR. Meanwhile, good dynamic and mechanical properties can also be achieved by increasing DPES content. SSBR with TEPE structure (SBTR) on the side chain was synthesized by copolymerizing styrene, butadiene and TPES. The interaction between SBTR and graphene (GNS) will be enhanced by the formation of covalent bond after thermal treatment of SBTR and GNS.The reaction between SBTR and GNS was confirmed by rotorless rheometer and X-ray photoelectron spectroscopy. The dispersion and mechanical properties were significantly increased by increasing the content of TPES in SBTR matrix. In this paper we provid a covalent approach for in situ enhancement of interaction between carbon based materials (CB and GNS) and SSBR by synthesizing of SBDR and SBTR.Meanwhile, SBDR and SBTR are hydrocarbon without any heteroatom.