Synthesis and Characterization of Novel Polyvinylether Polymers Produced Using Carbocationic Polymerization

Abstract

Using carbocationic polymerization, a series of novel polyvinylether polymers and copolymers were synthesized and characterized. A series of polysiloxane copolymers containing polymer grafts possessing Triclosan moieties (PTVE) were synthesized using living carbocationic polymerization followed by hydrosilylation and investigated for potential application as environmental friendly coatings to control biofouling on marine vessels and biomedical devices. Copolymers possessing a relatively low molecular weight polysiloxane backbone and relatively high PTVE content exhibited very high reductions in biofilm retention for S. epidermidis and moderate reductions for C. lytica and C. albicans. In the second example, a novel monoallyl-functional initiator that was capable of producing very fast initiation of the living carbocationic polymerization of chloroethyl vinyl ether was synthesized and characterized. The monoallyl-functional polymers were used to produce a series of block copolymers containing blocks of polyquaternary ammonium compounds and polydimethylsiloxane (PDMS-b-PCVE-b-PQ) using hydrosilylation followed by quaternization with an n-alkyldimethyl amine. The PDMS-bPCVE-b-PQ copolymers in solution showed very high antimicrobial activity toward E. coli and S. aureus when the n-alkyl chains attached to the nitrogens of the quaternary ammonium compounds are consisted of 12 - 14 carbons and 14 - 16 carbons, respectively. In the third example, a novel, highly brominated polymer was synthesized from pentabromo-6-ethoxybenzene vinyl ether (BrVE) using cationic polymerization. The thermal and rheological properties of the polyBrVE (PBrVE) were compared to a commercially available oligomeric brominated flame retardant, poly(pentabromobenzyl acrylate) (PBrBA). In addition, polymer blends based on polybutylene terephthalate (PBT) were prepared with the two brominated polymers and the thermal stability, mechanical, and rheological properties compared. The use of PBrVE resulted in lower melt viscosity and better compatibility in blends with PBT which would be expected to provide enhanced processability with regard to creating injection molded parts with relatively thin walls, such as those encountered in the electronics industry. Finally, a process was developed to obtain vinyl ether-functional monomers containing fatty acid pendent groups directly from soybean oil (SBO) using base-catalyzed transesterification. Moreover, a carbocationic polymerization process was developed for the vinyl ether monomers that allowed for high molecular weight polymers to be produced. Compared to SBO, which possesses on average 4.5 vinyl groups per molecule, the polyvinylethers based on the soybean oil-derived vinyl ether monomers (polyVESFA) can possess tens to hundredss of vinyl groups per molecule depending on the polymer molecular weight produced. As a result of this difference, coatings based on polyVESF A were shown to possess much higher crosslink density at a given degree of functional group conversion compared to analogs based on conventional SBO. In addition, the dramatically higher number of functional groups per molecule associated with polyVESF A results in gel-points being reached at much lower functional group conversion, which was shown to dramatically reduce cure-time compared to SBO based analogs.