Preparation Of Polydicyclopentadiene By Frontal Polymerization

Frontal polymerization(FP) is a novel polymerization technology which converts monomer into polymer by means of a localized propagates zone through coupling of the reaction released heat and the thermal diffusion. First, it should be provided shortterm heating to cause partial polymerization of the monomers, and the system by means of exothermic reaction triggers near monomers completing polymerization.Polydicyclopentadiene(PDCPD) is a type of thermosetting plastic, which is obtained by ring-opening metathesis polymerization of dicyclopentadiene(DCPD). The polymerization of DCPD have some features, such as a mass of reaction’s heat released, speed rate of polymerization and simple operation. Using the two-catalysts, the heat source triggers polymerization of local DCPD monomers at an adiabatic conditions, so PDCPD is prepared via FP.Adiabatic temperature rise of DCPD which occurs polymerization is calculated in an ideal situation, and it is determined that the reaction released heat of DCPD can guarantee FP theoretically. The reaction device and the measuring method were designed, with discovered the hybrids front propagates constantly change while changing time and the surface of polymer sample left polymerization blot, so it provided the evidence to the pure FP occurred according to anticipate. The paper researched effect of the heading mode, the amount of material rate and inhibitor amount about FP. It can be sure that the best heading mode is the water bath heating ascending FP mode by homemade reaction molding device in our laboratory, at the same time, monomer of DCPD, the main catalyst, cocatalyst ratio of amount of substance is 1200:1:20. As the mass fraction of inhibitor tetrahydrofuran(THF) enhances from 0.6% to 4.8%, the frontal velocity decreases from 4.82mm·min-1 to 0.81mm·min-1 and the frontal temperature also decreases from 132℃ to 74℃.PDCPD/CaCO3 nano-composites were prepared via FP by using nano-Ca CO3 as filling. The mechanical performance, thermal performance and morphology of the composites were studied. It can be concluded from the results that with increasing content of nano-Ca CO3, the impact strength, the tensile strength, the flexural strength and the hardness of the composites increase to different extent, but elongation at break of the composites decreases gradually. The impact strength improves by 100.3% when the mass fraction of nano-Ca CO3 is 4%; When the content of nano-Ca CO3 is 6%, the tensile strength increases by 7.5%; When the content of nano-CaCO3 is 7%, the flexural strength increases by 18.3%; The hardness improves by 15.5% when the mass fraction of nano-Ca CO3 is 7%. Tensile test curve shows that the composites are typically hard and tough materials. Known by the TGA that a certain amount of nano-CaCO3 will help to improve the thermal stability of the composites. The SEM indicates that the nano-CaCO3 are found to be dispersed in PDCPD matrix at the nanoscale and has a good combination of interface, this is probable reason to enhancing mechanism of nano-Ca CO3.PDCPD/OMMT nano-composites were prepared via FP by using OMMT as filling. The mechanical performance and morphology of the composites were studied. It can be concluded from the results that the the mechanical performances of the composites increase significantly when the mass fraction of OMMT is between 1% and 2%. When the content of OMMT is 2%, the impact strength grows by 63.3%, reaching 54.68 kJ·m-2. When the mass fraction of OMMT is 1%, the tensile strength is maximum, which has a marked decline when the content of OMMT rises to 3%. The hardness goes up sharply by mixing into OMMT, and the most hardness occurs by 2% OMMT. The TEM illustrates that OMMT, which content is 1%, is completely exfoliated for the monolithic structure of without regular arrangement, with dispersing in PDCPD matrix at the nanoscale. Whilst, the most of OMMT’s intercalated structure mix into the matrix, accompanying a part of completely exfoliated type and a little aggregation, it shows the best content of OMMT is 1%; at the same time, XRD also determines the above result.