50results about How to "Reasonable molecular weight distribution" patented technology

The invention provides an optical-grade PMMA (polymethyl methacrylate) continuous bulk polymerization method and production system. The method comprises the following steps: mixing reaction raw materials methyl methacrylate, initiator and assistant according to proportions to obtain mixed solution, performing metering, then injecting the mixed solution into a continuous polymerization reactor to perform polymerization reaction and continuous extrusion, and performing devolatilization treatment after extrusion to obtain a PMMA solid material. By dispersing and thinning the materials through screw-type shaft body rotation and shearing, the molecular weight of the materials is enabled to be reasonably distributed, the mixing uniformity of reaction components is improved, the reaction components are enabled to exchange heat with a machine barrel wall and a shaft outer wall in time, the entire process is continuous, the material retention time is reduced, the probability of heat accumulation is reduced, the temperature gradient between the materials is reduced, the problem of reaction heat control of bulk polymerization is solved and finally the continuous extrusion of the product in the reaction process is realized.

The embodiment of the invention provides a liquid phase synthesis method of high isotactic polybutene-1 and belongs to the field of high-molecular polymer synthesis. With adoption of the liquid phase synthesis method of the high isotactic polybutene-1, a polymer with reasonable molecular weight distribution can be acquired according to the principle of reaction kinetics while the subsequent separation energy consumption is reduced. The liquid phase synthesis method of the high isotactic polybutene-1 comprises the following steps: adding a butane-1 monomer, a supported titanium catalyst, a cocatalyst, and mixed liquid of an electron donor and an inert solvent in a loop reactor sequentially, taking hydrogen as a molecular weight regulator and inert gas as a pressure regulator in the loop reactor, carrying out programmed temperature increasing within a preset temperature range under the condition of enabling the reaction pressure in the whole loop reactor to keep in a preset pressure range by regulating the partial pressure ratio of the inert gas, carrying out constant-pressure reaction for 1-4h, carrying out flash evaporation to remove the unreacted monomer, and obtaining the powdery high isotactic polybutene-1. The liquid phase synthesis method can be used for industrial production of the high isotactic polybutene-1.

The invention discloses a preparation method of an environment stress cracking resistant blow molding material special for an auto plastic fuel tank. The preparation method comprises the following steps: (1) under the condition that a diluent is always in a circulating state and in the presence of a catalyst, placing raw materials including ethylene and 1-hexene into a reaction vessel for reacting, wherein the reaction temperature is 94 to 100 DEG C, and the reaction is stopped when the melt flow rate of a reaction product reaches 5.3 to 6.5g / 10min and the density is 0.943 to 0.947kg / m<3>, so as to obtain ethylene hexene copolymerization polyethylene resin; (2) taking and uniformly mixing 99.50 to 99.80 parts of ethylene hexene copolymerization polyethylene resin, 0.05 to 0.35 part of antioxidant, 0.03 to 0.15 part of auxiliary antioxidant and 0.02 to 0.06 part of zinc stearate, then adding the same into a mixing mill for extrusion pelletization, and cooling particles in cooling water; the obtained blow molding material special for the auto plastic fuel tank has relatively high melt strength, excellent environment stress cracking resistance and creep resistance, and good chemical corrosion resistance, and is suitable for machine shaping of single-layer and multilayer auto plastic fuel tanks.