Research On Modification Of Hyperbranched Polyester

First,hyperbranched polyester?HBP?based on trimethylol propane and dimethylol butanoic acid was synthesized.Followed by end-modifing with maleic anhydride,end-modified polymer with unsaturated end groups?UEHBP?was successfully synthesized.The UV curable film based on HBP,1173 as photoinitiator,and LaromerR TPGDA as reactive diluent was obtained.The structures of polymers were characterized by FI-IR,¹H NMR and ¹³C NMR,respectively.The reaction process was tracked by acid value titration,and the degree of reaction was determined by hydroxyl value titration.The water-solublityofpolymerwasmeasuredthroughspectrophotometer.Then,hyperbranched polyurethane?HBPU?for phase change material was prepared from HBP and PEG-NCO as a modifier.The structure and phase change behavior of polymers were characterized by FT-IR,DSC and TGA.Finally,the other hyperbranched polyester polymer?HBP-1?was prepared by the self-polycondensation of an AB₂ type monomer,DMBA.Followed by end-modified with maleic anhydride,end-modified HBP-1 with unsaturated end groups was successfully synthesized.Moreover,The UV curable film based on HBP-1,1173 as photoinitiator,and LaromerRTPGDA as reactive diluent was obtained.The results show that the degrees of branching?DB?of HBP derived from TMP and DMBA was 0.53.The C=C double bond and carboxyl were successfully introduced into the end groups of HBP modified by maleic anhydride,and the resulting polymer maybe used as a photosensitive material.When the amount of photoinitiator and reactive diluent was 4%and 15%,respectively,the exposure time was 60s,the UV-cured polymer film had excellent performances.The melting peak and phase chang enthalpy of phase change material,which was prepared from HBP,and PEG-MDI or PEG-IPDI polyurethane prepolymers as a modifier,were 66.3?,71?and 148.7J/g,142.5J/g,respectively.The HBP-1 was prepared by the polycondensation of DMBA,and DB was 0.69.The HBP-1has higher DB compared as HBP.