Preparation of stable polymeric grafted layers on poly(ethylene terephthalate) by thermal annealing

Abstract

This work presents a simple and versatile grafting method to prepare stable polymer layers on poly(ethylene terephthalate) (PET). Poly(styrene-co-2-hydroxyethyl methacrylate) was synthesized by free radical polymerization. The copolymer was grafted onto poly(ethylene terephthalate) via the hydroxyl groups upon thermal annealing. The percentage of copolymer grafting was studied as a function of copolymer composition, PET surface treatment, annealing time, and annealing temperature. The grafted polymer layer on PET remained stable when immersed in an organic solvent whereas the non-grafted polymer layers were completely desorbed within two weeks. In addition, poly(4-vinylpyridine-co-2-hydroxyethyl methacrylate) was grafted onto PET to test the versatility of this grafting method. Control experiments were carried out to demonstrate that the grafting occurs through the available hydroxyl groups on the polymers and the surfaces. Based on these results, this grafting method offers a simple and versatile strategy to prepare stable polymeric layers on polymeric surfaces, and therefore, expands the tool box for functionalizing polymer surfaces.

On the preparation of EPDM-g-MAH compatibilizer via melt-blending method

“…The presence of new singlet from the peak of 4.00 ppm is the effect of ene reactions [17]. The absence of resonant at peak 6.50 ppm in the 1 H-NMR spectra for the EPDM-g-MAH sample and its control sample, explains that terpolymer MAH has been detected from this analysis [31][32][33][34]. The grafting MAH reaction mechanism into EPDM visualized as in the following Figure 11.…”

“…Those figures are original results that taken directly from the NMR machine and presence of noise and its background colour need to be ignore due to machine set-up, standard results and machine condition. The EPDM-g-MAH compatibilizer synthesized by using an internal mixer, which gives shearing effect that can help in breaking the chain [32,33]. The presence of dicumyl peroxide initiator in very small quantities as shown in reaction schematic (1), has formed the start-up radical for reactive grafting reaction of EPDM rubber.…”

“…The presence of DCP initiator in certain small quantity has helped in increasing the number of EPDM active radicals for the reaction with MAH. In the reaction schematic path (3), the MAH molecules added during the melt-blending were found to react with EPDM active radicals and grafting occurred in the formation of EPDM-g-MAH radicals, followed by several possibilities for termination reactions, based on two paths of reaction options [32,33,34]. Option (1) shows the EPDM-g-MAH radicals may undergo hydrogen transfer from other polymer chains, whereas option (2) shows the possible radical reaction of EPDM-g-MAH with other radicals in the melt blending system such as MAH, EPDM or primary radicals to form different EPDM-g-MAH structures [9].…”