The Investigation Of Polyolefin Grafted With Maleic Acid Lanthanum Ionomers

Ionomers consist of inorganic ions and organic molecules, and they have many unique properties compared with common polymers. The ionomers are usually used as the compatibilizer, nucleating agent and stabilizer in modification of polymers. In this study, a kind of metal complexes were synthesized which contained unsaturated bond, and the metal complexes were used to synthesize ionomers by the method of melt grafting. The properties of the ionomers were also studied.Lanthanum chloride and maleic acid were used to synthesize lanthanum maleate complexes (LaA) by the method of direct precipitation, and the complexes were characterized by many analysises. The reaction conditions were also optimized in this study. The results showed that the coordination forms of complexes might be bridged and chelate. The complexes had excellent thermal stability and solvent resistance. When the pH was4.5, the maximum conversion rate of lanthanum ion was72.48%, and it was70.52%when the pH was7.0.The polyethylene (PE), polypropylene (PP), lanthanum maleate complexes (LaA), dicumyl peroxide (DCP) and glycolic acid were used to prepare polyethylene grafted lanthanum maleate ionomers (PE-g-LaA) and polypropylene grafted lanthanum maleate ionomers (PP-g-LaA). The ionomers were prepared by melt grafting method, and they were characterized by many analysises. The results showed that the crystallization peak temperature (Tc) of the ionomers increased compared with pure PE (PP) respectively, indicating that the ionomers could promote the crystallization of PE (PP). In addition, the loss modulus and storage modulus of the ionomers were higher than pure PE (PP) respectively.Polyethylene grafted lanthanum maleate ionomers ionomers (EMA) was added into polycaprolactam/polyethylene (PA6/PE) blends as the modification agent, and the PA6/PE blends were characterized by many testings. The results showed that the crystallization temperature (Tc) decreased a little with the addition of EMA, which meaned that EMA hindered the crystallization of PA6. It also showed that EMA could improve the compatibility of the PA6/PE blends effectively. With the increasing of EMA content, the size of dispersion phase particles became samaller in the PA6/PE blends. When the EMA content went to4wt%, the blends had better dispersion effect, and continued to add EMA, the size dispersed phase particles decreased no more. Compared with the unmodified blends, the loss modulus and storage modulus of the modified blends improved as well as the mechanical properties. Compared with the unmodified PA6/PE blends, the modified blends had higher loss modulus and storage modulus. With the increasing of EMA content, the melt modulus of the blends increased. The mechanical properties of PA6/PE blends could be enhanced by the EMA. When the dosage of EMA was4wt%, the blends had better comprehensive mechanical properties.The maleic acid lanthanum complexes (LaA), maleic acid lanthanum/calcium carbonate (LaA/CaCO3) and PE-g-LaA ionomer (EMA) were used as the nucleating agent to modify polypropylene (PP), and the crystal properties of modified PP were studied. It was showed that LaA, LaA/CaCO3and EMA could improve the crystallization peak temperature (Tc) of PP, so the modifiers might improve the crystallization properties of PP. What’s more, the modifiers could only produce the alpha spherulite of PP, so they were alpha nucleating agent of PP.