Surface photografting polymerization of vinyl acetate, maleic anhydride, and their charge‐transfer complex. V. Charge‐transfer complex (1)

Abstract

ABSTRACT:In previous studies, the photografting polymerization of vinyl acetate (VAC) and maleic anhydride (MAH) was investigated systematically. After that, to increase the grafting rate and efficiency and make the project more practicable, a VAC-MAH binary monomer system was employed for simultaneous photografting onto the surface of low-density polyethylene film. The effects of several crucial factors, including the composition and total concentration of the monomer solution and different types of photoinitiators and solvents, on the grafting polymerization were investigated in detail. The conversion percentage (CP), grafting efficiency (GE), and grafting percentage were measured by gravimetry. The results showed that the monomer composition played a big part in this binary system; appropriately increasing the content of MAH in the monomer feed was suited for grafting polymerization. The growth of the total monomer concentration, however, made the copolymerization faster and was unfavorable for grafting polymerization. The three photoinitiators-2,2-dimethoxy-2-phenylacetophenone (Irgacure 651), benzoyl peroxide, and benzophenone (BP)-led to only slight differences in CP, but for GE, BP was the most suitable. As for the different solventsacetone, ethyl acetate, tetrahydrofuran (THF), and chloroform-using those able to donate electrons (acetone and THF) resulted in relatively higher CPs; on the contrary, the use of the other solvents made GE obviously higher, and this should be attributed to the charge-transfer complex (CTC) that formed in this system.

Nondestructive Covalent “Grafting-from” of Poly(lactide) Particles of Different Geometries

“…Instead, a broadening of the PLA CO band was observed, which would be the case if the amount of MAH grafted onto the PLA were low. It has previously been shown that MAH is difficult to homopolymerize and it is most often found in copolymers. − MAH will thus form something similar to a monolayer on the substrate which would be difficult or impossible to observe with FTIR, since the depth of analysis of FTIR is approximately 1 μm. This means that a quite thick graft layer is required to prevent measurement of the bulk material as well.…”