Functionalization And Modularization Of Polypropylene Based On Chain Transfer Reactions Of Dialkylzincs

The thesis is dedicated to the functionalization and modularizationof polypropylenein the presence of dialkylzincs as chain transfer agents. We demonstrated the alkylexchange reaction in conventional metallocene/MAO catalyst system. Modularsynthesis of azide-and alkyne-functionalized polypropylene, ethylene/propylenecopolymer, propylene/octene copolymer and telechelic polypropylene were achievedwith rac-Me2Si[2-Me-4-Ph-Ind]2ZrCl2/AlR3/CPh3B(C6F5)4/ZnR’2catalyst system. Thecombination of these module led to Long Chain Branched polypropylene,polypropylene di-and tri-block copolymer.1) Alkyl exchange reaction in metallocene/MAO/ZnR2catalyst system.Alkyl exchange between diethylzinc and MAO led to a new dialkylzinc coumounddimethylzinc, and polymer structures can be effected greatly. At all events, two chaintransfer agent ZnR2and ZnMe2existed in rac-Me2Si[2-Me-4-Ph-Ind]2ZrCl2/MAO/ZnR2catalyst system, and both of which functioned as chain transfer agents toproduce polymers with different structures.2) Synthesis of azide-terminated and alkyne-grafted polypropylene and productionof LCBPPZinc-terminated iPP chain iPP-Zn was produced from chain transfer to dialkylzincsin propylene polymerization catalyzed by rac-Me2Si[2-Me-4-Ph-Ind]2ZrCl2/AlOct3/CPh3B(C6F5)4/ZnR2ctalyst system, and iodonation of iPP-Zn producediodo-terminated polypropylene iPP-I, which was then transformed to azide-terminatediPP (iPP-N3) with NaN3. A definitely new process to produce alkyne-grafted iPP(iPP-g-≡) with high efficiency was developed using hydroxyl-grafted iPP (iPP-OH) as a reactant and propynylamine as alkyne source. iPP-N3and iPP-g-≡were then linkedwith click reaction to produce LCBPP. Detailed characterization by1H NMR, IR,GPC, DSC and viscosity showed the highly efficient yield.3) Synthesis of alkyne-terminated ethylene/propylene copolymer and production ofpolypropylene di-block copolymerAlkyne-terminated ethylene/propylene copolymer (EP-≡) was obtained byethylene/propylene copolymerization with dialkylzincs as chain transfer agentsfollowed by oxidation, hydroboration-oxidation and alkynation. Click reaction wasconducted with two groups of iPP-N3and EP-≡samples to obtain four iPP/EP blockcopolymers (iPP-b-EP).1H NMR, IR, DSC and GPC analysis showed the quantitativetransformation of azide and alkyne groups to triazole.4) Synthesis of telechelic polypropylene and polypropylene tri-block copolymerTelechelic polypropylene and octene/propylene copolymers were obtained withrac-Me2Si[2-Me-4-Ph-Ind]2ZrCl2/AlR3/CPh3B(C6F5)4/ZnEt2catalyst system.Cyclohexenyl-and hydroxyl-terminated telechelic iPP were transformed tobis-hydroxyl-terminated iPP HO-iPP-OH, which were then used for alkynationprocess to produce bis-alkyne-terminated iPP≡-iPP-≡; Mesylation process wasconducted with mono-hydroxy-terminated propylene/octene copolymer PO-OH toobtain mono-mesylate-terminated propylene/octene copolymer PO-OMs, and themesylate group in PO-OMs was then substituted by azide group to producemono-azide-terminated propylene/octene copolymer PO-N3. The click couplingreaction between≡-iPP-≡and PO-N3produced PO-b-iPP-b-PO tri-block copolymer.1H NMR, IR, DSC and GPC analysis showed the quantitative transformation of azideand alkyne groups to triazole.