Graft copolymerization of p‐acryloyloxybenzoic acid and p‐methacryloyloxybenzoic acid onto isotactic polypropylene and their thermal properties: Part I

Abstract

ABSTRACT:The polymerization and grafting of the monomers p-acryloyloxybenzoic acid and p-methacryloyloxybenzoic acid were studied. Poly(acryloyloxybenzoic acid) was obtained by g-radiation-induced solution polymerization and bulk melt polymerization initiated by dicumyl peroxide. Poly(methacryloyloxybenzoic acid) could be obtained only by bulk melt polymerization. The graft copolymerization of the monomers onto isotactic polypropylene was carried out in bulk. The maximum grafting was reached in shorter times at higher temperatures, and it also increased with the concentration of the monomers in the reaction medium. The thermal and crystallization behavior of the graft copolymers was studied with differential scanning calorimetry and wide-angle X-ray diffraction. The graft copolymerization of p-acryloyloxybenzoic acid did not have any influence on the formation of both a forms (monoclinic) of polypropylene, whereas p-methacryloyloxybenzoic acid led to the a 2 form. The b-crystalline modification (hexagonal) formed in poly(acryloyloxybenzoic acid)-g-polypropylene products at 1858C and at higher grafting temperatures and also in the second run of differential scanning calorimetry studies after fast cooling. The b form was not observed in graft copolymers of poly(methacryloyloxybenzoic acid).

Thermal stability and decomposition mechanism of poly(p‐acryloyloxybenzoic acid and poly (p‐methacryloyloxybenzoic acid) and their graft copolymers with polypropylene, Part II

“…The thermal properties of graft copolymers of PABA‐ g ‐PP and PMBA‐g‐PP were presented previously 7. We have detected that PABA and PMBA started to decompose before completing the melting endotherm in grafted samples.…”

“…Poly( p ‐acryloyloxybenzoic acid), PABA was obtained by γ‐irradiation induced polymerization and by bulk polymerization with dicumyl peroxide (DCP at 202°C) initiation, and the graft copolymers PABA‐ g‐ PP and PMBA‐ g ‐PP were produced by bulk melt polymerization as described in previous work 7. Poly ( p ‐methacryloyloxybenzoic acid), PMBA was obtained only by bulk melt polymerization as it was reported in literature 4…”

“…In our previous manuscript the polymerization and grafting process of both monomers were discussed 7. The monomers were polymerized in bulk at high T , and using an initiator (dicumyl peroxide) and also γ‐irradiation in solution.…”

Reinforcement of high density polyethylene with a side chain LCP by graft copolymerization—thermal, mechanical and morphological properties

“…With the presence of both the nanosilica particles and LCP, the LCP/PP/SiO 2 system possessed dual reinforcements and exhibited the highest strength and modulus amongst the composites [21]. In one of our foregone studies [22], as an alternative consideration on LCP-PP combinations, side chain LCP molecules were formed on PP chains as graft units by graft copolymerization of the vinyl monomers to improve the properties of PP. Due to their regular and organized structure, side chain LCP graft units in the copolymers were hypothesized to have led to additional orientation and alignment of PP chains besides the probable fibrereinforcement effect reported [6], thus to enhanced mechanical properties in the material.…”

Aplicaciones de radiación gamma y UV para el injerto molecular y el diseño de matrices para aplicaciones terapéuticas

“…Una ventaja de este método es la posibilidad de almacenar el polímero irradiado a baja temperatura por un tiempo considerable. Además se reduce considerablemente la formación de homopolímero [22][23][24][25][26][27][28]. Una desventaja es la posible degradación del polímero.…”