Reactive extrusion of polypropylene with supercritical carbon dioxide: Free radical grafting of maleic anhydride

Abstract

A reactive extrusion process for the functionalization of polypropylene with maleic anhydride in the presence of supercritical carbon dioxide was studied. Supercritical carbon dioxide was used in this reactive extrusion system to reduce the viscosity of the polypropylene melt phase by forming a polymer-gas solution in order to promote better mixing of the reactants. Subsequently, the effect of supercritical carbon dioxide on the level of grafting, product homogeneity, and molecular weight was evaluated. Analysis of the products revealed that the use of supercritical carbon dioxide led to improved grafting when high levels of maleic anhydride were used. The experimental results showed no evidence of an improvement in the homogeneity of the product, while melt flow rate measurements showed a reduction in the degradation of polypropylene during the grafting reaction when low levels of maleic anhydride were employed.

Grafting of maleic anhydride on polypropylene by reactive extrusion: effect of maleic anhydride and peroxide concentrations on reaction yield and products characteristics

“…Grafting was initially conducted in solution [2][3][4] or in batch in the melt state [2,[5][6][7][8]. However, it is now common to produce grafted PP by reactive extrusion, using twin screw extruders as continuous reactors [9][10][11][12][13][14][15][16][17][18][19][20][21]. A major advantage of the reactive extrusion process is avoidance of the use of solvent, but the high temperatures encountered in extrusion can also lead to secondary reactions, like β-scissions for the PP [22,23].…”

Ethylene Butyl Acrylate Glycidyl Methacrylate Terpolymer as an Interfacial Agent for Isotactic Poly(propylene)/Wood Flour Composites

“…attributed to poor compatibility between the polar hydrophilic wood flour and the non-polar hydrophobic iPP matrix, and also to the poor dispersion of wood flour in iPP matrix due to the strong interactions between wood particles resulting from hydrogen bonding. [4,6] In this regard, many papers have been published on the different methods used for improving interfacial adhesion, and these could be performed through either polymer or filler modification, or the addition of a third component, i.e., a coupling agent. [7][8][9][10][11][12][13][14] As a matter of fact, most data reported in the literature is devoted to maleated poly(propylene) (MAPP) and its role as a compatibilizer in iPP/WF composites due to its effectiveness in improving both the tensile and flexural strengths of the materials.…”

Waste and Virgin LDPE/PET Blends Compatibilized with an Ethylene‐Butyl Acrylate‐Glycidyl Methacrylate (EBAGMA) Terpolymer, 1

“…[10][11][12] A wide range of reactive compatibilizers have been effectively tested and the first successful one used was a styrene-butadiene-styrene (SBS) block copolymer. [13,14] Maleic-anhydride-grafted polyolefins, [15][16][17] acrylic acid copolymers, [18] ethylene glycidyl methacrylate (EGMA) copolymers, [19,20] and ethylene/ethyl acrylate glycidyl methacrylate terpolymers (E-EAGMA) [21] are other compatibilizers that have been used for polyolefin/PET blends. By considering the work published so far, it should be stressed that there is no ready answer to which compatibilization approach is the best for polyolefin/PET blends.…”