5results about How to "Raise the crystallization temperature" patented technology

The application discloses a method for improving crystallization ability of semi-aromatic nylon and modified semi-aromatic nylon. The method comprises the following steps: mixing semi-aromatic nylon and an alkaline solution, and preparing the modified semi-aromatic nylon after heat treatment; the mass ratio of the alkali in the alkaline solution to the semi-aromatic nylon is greater than or equal to 0.005:1; the alkali in the alkaline solution comprises hypophosphite, phosphite, phosphate or alkali metal salt; and the temperature of the heat treatment is greater than 60 DEG C. The method can improve the crystallization ability of the semi-aromatic nylon without adding nucleating agents, additives and the like, for example, improving the crystallization ability of the semi-aromatic nylon under the conditions that the polymerization process and the polymer molecular weight are determined.

The application relates to the technical field of high polymer materials, and discloses a nylon material and a preparation method and application thereof. The nylon material comprises the following preparation raw materials in percentage by mass: 70-85% of nylon resin, 8-15% of nitrogen-based flame retardant, 2-8% of phosphorus-based flame retardant and 1-8% of synergistic flame retardant. The nylon material provided by the application adds the phosphorus-based flame retardant and the synergistic flame retardant in a traditional nitrogen-based flame retardant system, so that the ignition temperature of the material is increased, the dropping speed and the dropping ignition probability are reduced, and the flame retardant performance of the material is improved. The ignition temperature of the material can reach 745 DEG C, the DSC crystallization temperature can reach 187 DEG C, the demolding effect is good, the dropping speed is slow, the dropping ignition probability is low, the performance requirements of a battery assembly product on the material can be met, and the nylon material can be used in the preparation of electronic connectors, battery compartments, low-voltage switches, housings or terminal blocks of power distribution systems of electronic and electrical equipment.

The method for preparing polyoxalate by ring-opening polymerization of cyclic oxalate monomers and cyclic oligomers thereof disclosed by the application is that at least one of the cyclic oxalate monomers and the cyclic oligomers thereof, or a blend of at least one of the cyclic oxalate monomers and the cyclic oligomers thereof and at least one of cyclic lactone, cyclic lactide and cyclic carbonate, is subjected to bulk ring-opening polymerization or solution ring-opening polymerization under the action of a catalyst and an initiator to obtain polyoxalate and its copolymer. Since the application adopts ring-opening polymerization to prepare polyoxalate, not only the problems of low esterification polycondensation efficiency and poor polymerization controllability are avoided, but also the side reactions of alpha-keto acid decarboxylation and terminal hydroxyl group etherification in the esterification polycondensation process are avoided, so that the polyoxalate obtained has controllable polymerization degree / molecular weight, high structural regularity and clear end group structure, and further has higher melting point and crystallization temperature and is white, and at the same time, a new way for preparing polyoxalate is provided.

The application belongs to the technical field of polymer materials, and particularly relates to a kind of methylene furan-containing aromatic skeleton double urea nucleating agent, heat-resistant polylactic acid composition and a preparation method thereof. A series of methylene furan-containing aromatic skeleton double urea polylactic acid nucleating agents are prepared by a green route using non-isocyanate as raw material, and a furfurylamine derived from biomass by a one-pot two-step method. In the polylactic acid composition, the mass content ratio of polylactic acid and nucleating agent is 100:0.1-5. Dry polylactic acid and methylene furan-containing aromatic skeleton double urea nucleating agent are mixed by a double-screw mixer at 150-220 DEG C for 3-15 min. The polylactic acid composition modified by the nucleating agent has a significant improvement in crystallization rate and crystallinity, and the heat resistance is further enhanced, so the composition has a good industrialization prospect.

The invention relates to the technical field of high polymer materials, and discloses a low-density biodegradable composite material based on an interface pore effect and a preparation method. The composite material is prepared from a resin matrix composed of poly (butylene adipate / terephthalate) and polypropylene carbonate, modified activated plant fibers, a high-melting-point heterogeneous crystallization nucleating agent and a matrix reinforcing chain extender, wherein the surfaces of the modified activated plant fibers are grafted with nano rigid particles, and the modified activated plant fibers are passivated by polyethyleneimine. The preparation method comprises the following steps: firstly, grafting nano particles on the surface of the fiber through a silane coupling agent, passivating, and then reacting and extruding under a high vacuum condition through a double-screw extruder with the length-diameter ratio of greater than or equal to 52: 1. According to the invention, the density of the material is reduced on the premise of not adding a chemical foaming agent by utilizing an interface micropore nucleation principle, meanwhile, the problem of matrix degradation caused by plant fibers is solved, and the composite material with the characteristics of light weight, high strength and full biodegradation is obtained.