Research On The Synthesis And Performance Of Functional Polyolefin Copolymer

The functionalization of polyolefins play an important role in the modification and expanded application of the non-polar polyolefin materials, so it has been one of research hot spots of academia and industry. Functional polyolefin graft copolymer is one of the target product of polyolefin functionalization, there are mainly three methods:grafting onto, grafting from, grafting through. In this thesis, a series of functional graft copolymer EVAL-g-PS based on polyolefin main chain and PS as side chain were synthesized via atomic transfer radical polymerization(ATRP). The application of the graft copolymer in the fabrication of ordered microporous films and using as compatibilizer were primarily researched.(1) EVAL was prepared by the hydrolysis of EVA, and the macroinitiator EVAL-Br was synthesized by the transformation of hydroxyl on the side chain, and ATRP of styrene were then carried out using such macroinitiator prepare graft copolymer EVAL-g-PS, the chain structure, molecular weight and its distribution of such graft copolymer were characterized by high temperature 1H NMR and GPC.(2) After observing the cryofractured surfaces of the two blend systems LDPE/PS and EVA/PS via SEM, EVAL-g-PS is tested to be a good compatibilizer to the above blend systems, since the addition of it can effectively improve the surface energy of two incompatible materials, thus homogenized and high performance blending material can be obtained.(3) By controlling solvent, polymer concentration, environmental vapor, the EVAL-g-PS were performed to fabricate honeycomb microporous films or microspheres films via a static BF process for the first time. The film morphology was investigated via SEM. We further summarized how the factors which were mentioned above impact the morphology of such microporous films. After the UV radiation, the improvement of the copolymer films’ wettablity was confirmed by the results of water droplet contact angle.The results indicate that the graft copolymer EVAL-g-PS (Mn=3.8-11.8×104g/mol, PDI=2.31-4.66) can be synthesized via ATRP of styrene using the macroinitiator under 100 ℃, and the reaction time is 20 h. The obtained copolymer can be applied as compatibilizer in the blend systems of LDPE/PS and EVA/PS. The copolymers can also be used in the fabrication of ordered microporous films in the solution of CHCl3 at the temperature of 22 ℃ and R.H.=95% with the average diameter of the porous is 2.4-3.8 μm.