Preparation And Properties Of Six-membered Semi-melon Ring Doped Polypropylene Composite

Based on classical nucleation theory and molecular structure,hemicucur[6]uril(HQ6)was chosen as an organic nucleating agent in the polypropylene(PP)foam injection molding process in this paper.According to the findings,HQ6 has a natural cavity advantage for improving the properties of PP composites and forming bubble holes.However,because of its flexible large ring structure,HQ6 causes shear deformation during processing,which has a negative impact on the performance of PP composites.As a result of the defects in the HQ6 structure,composite modification was performed,and the properties of the HQ6 composite doped polypropylene composite were investigated as follows.In this study,a novel β-nucleating and foaming nucleating agent(HQ6@EA)of PP was synthesised by hemicucurbit[6]uril(HQ6)complexed with ethanedioic acid(EA)through the solution method.Results showed that HQ6 and EA bonded together through non-covalent bond force,and the morphology changed obviously.The maximum content of β-PP was 15.34% with 0.5 wt.% addition of HQ6@EA,and the crystallisation rate,decomposition temperature and crystallinity of the nucleated PP were improved by HQ6@EA.The nucleated PP foaming material was processed through injection moulding with azodicarbonamide as the foaming agent and HQ6@EA as the nucleating agent.The average cell size of the foamed composite was reduced by about two times compared with that of pure PP,and the cell density was increased by about 6.5 times when the added content of HQ6@EA was 0.5 wt.%.The mechanical properties of PP composited with HQ6 and HQ6@EA with loading of0.25 wt.% to 5.0 wt.% were investigated.Among the various filler types studied,HQ6@EA with loading of 0.5 wt.% exhibited a considerable improvement in impact strength relative to the pure PP.In this study,HQ6 complexed with graphene oxide(GO)was synthesised through solution method.HQ6@GO was assessed by Fourier transform infrared and Raman spectroscopy,thermal and X-ray powder diffraction analysis.Results showed that HQ6 and GO bound together by non-covalent bond force.PP foaming material was processed through injection moulding with azodicarbonamide as the foaming agent and HQ6@GO as the nucleating agent.The effect of HQ6@GO on the properties of the PP composite material,such as crystallisation was assessed.Result showed that HQ6@GO can increase the crystallisation rate,and the crystallinity was increased from 37.26% for pure PP to 43.24% for PP/HQ6@GO composites.HQ6@GO showed the best foaming nucleation effect,with 1.0 wt% addition of HQ6@GO,the average cell size decreased by about 3 times,and the cell density was increased by about 10 times compared with pure PP.The tensile and impact properties of the foamed composite material were systematically studied.Particles with well dispersion and improved quality of cells could improve the mechanical strength of composites.