Melt grafting of glycidyl methacrylate onto polypropylene and reactive compatibilization of rubber toughened polypropylene

Abstract

Free radical melt grafting of glycidyl methacrylate (GMA) onto polypropylene (PP) was studied. The extent of GMA grafting and the molecular weight of the functionalized PP copolymers were controlled by carefully manipulating various reaction factors, such as monomer concentration, initiator concentration, reaction temperature, and molecular weight of the starting PP homopolymer. The use of a second monomer, styrene, in the grafting process helped to increase GMA grafting further and reduce chain scission. The GMA modified PP copolymer was found to be able to reactively compatibilize PP/acrylonitrile‐co‐butadiene‐co‐acrylic acid rubber (NBR) blends. Up to an eight‐fold increase in the impact energy of the PP/NBR blend was obtained. The compatibilizing capacities of the reactive copolymers, in terms of impact energy improvement of the PP/NBR blend, were found not to be exclusively dependent on the total concentration of reactive functionalities in the matrix of the blend. The characteristics of the reactive copolymers, i.e., the extent of functionalization and the molecular weight, were found to have significant influences on the compatibilizing capacity. A large amount of moderately functionalized copolymer offers better compatibilization performance than a small amount of highly functionalized copolymer. A significant drop in impact energy was observed with declining molecular weight of the copolymer.

Synthesis and Characterization of Functionalized Crosslinkable Poly(ε‐caprolactone)

“…GMA has two reactive functions, the double bond and the epoxy group. [17,18] The latter is highly electrophilic and is able to react with many functional groups, such as carboxyl or hydroxyl groups, [19] and its reactivity towards anhydride groups is reported to be particularly fast; [20] such a reaction can be even more favored by the presence of traces of maleic acid (present in the starting MA), which acts as nucleophile towards the epoxy function of GMA, with the consequent opening of the epoxy and anhydride rings and the formation of a hydroxyl group and an ester linkage. Besides, the molar excess of MA compared to GMA confirms the possibility that part of the MA gives rise to a condensation reaction with the epoxy of GMA in the course of the grafting process, and part is grafted as cyclic anhydride.…”

An investigation on the role of GMA grafting degree on the efficiency of PET/PP-g-GMA reactive blending: morphology and mechanical properties

“…In other words, epoxy functional groups in the GMA chemical structure cerate bond with other functional groups such as hydroxyls, amines, and anhydrides, and assist in free-radical grafting reaction with their unsaturated groups [22,25]. From this perspective, thermoplastics polymers have widely been modified with GMA via melt free-radical grafting [28][29][30]. Awkwardly, however, the conversion of GMA grafting reaction on PP backbone was not sufficient even with excessive amount of peroxide in the system [31].…”

Morphology, structure, and rheological property of linear low‐density polyethylene grafted with acrylic acid

“…The monomers grafted onto polyolefins usually are unsaturated functional monomers, such as maleic anhydride (MAH), [1][2][3][4] glycidyl methacrylate (GMA), [5][6][7] acrylic acid (AA) 8,9 and its derivatives, and so forth. The properties and applications of these grafting functionalized polyolefins are very much dependent on the nature and degree of grafting (DG) of the monomers used.…”