0000000000041388
AUTHOR
Danuta Sek
Compatibilization of blends of polyethylene with a semirigid liquid crystalline polymer by PE-g-LCP copolymers
The blends of thermoplastics with liquid crystalline polymers show, in general, poor properties because of the lack of adherence between the two phases. The use of ad hoc synthesized copolymers containing the monomer units of the two polymers has been recently considered by some of us for blend compatibilization, and the results appear promising. In this work, new PE-g-LCP copolymers, prepared either by the synthesis of the LCP in the presence of a functionalized PE, or by reactive blending of the latter polymer with preformed LCP, have been employed as compatibilizing additives for blends of PE with a semirigid LCP. The morphology and the rheological and mechanical properties of the ternar…
Synthesis of PP-LCP graft copolymers and their compatibilizing activity for PP/LCP blends
The aim of this work was the synthesis of new graft copolymers consisting of polypropylene (PP) backbones and liquid crystalline polymer (LCP) branches, to be used as compatibilizing agents for PP/LCP blends. The PP-g-LCP copolymers have been prepared by polycondensation of the monomers of a semiflexible liquid crystalline polyester (SBH 1 : 1 : 2), that is, sebacic acid (S), 4,4′-dihydroxybiphenyl (B), and 4-hydroxybenzoic acid (H) in the mole ratio of 1 : 1 : 2, carried out in the presence of appropriate amounts of a commercial acrylic-acid-functionalized polypropylene (PPAA). The polycondensation products, referred to as COPP50 and COPP70, having a calculated PPAA concentration of 50 and…
Morphology and Rheology of HDPE/LCP Blends Compatibilized by a Novel PE-g-LCP Copolymer
A novel graft copolymer (PE-g-LCP) consisting of polyethylene (PE) backbones and liquid crystalline polymer (LCP) branches was synthesized via reactive blending of an acrylic acid-functionalized PE (Escor 5000 by Exxon) with a semiflexible LCP (SBH 1 : 1 : 2 by Eniricerche S.p.A.). The crude reactive blending product (COP) was shown by investigation of the fractions soluble in boiling toluene and xylene and of the residue to contain unreacted Escor and SBH, together with the graft copolymer forming the interphase. The compatibilizing activity of COP for PE/SBH blends, compared to that of pure Escor, was investigated using two PE grades. The COP addition into 80/20 PE/SBH blends caused a muc…