Nowadays, the role of modified plastics in national life is becoming more and more important, especially in the fields of automobiles and home appliances. For the modified plastics technology, plastic toughening technology has been studied and paid attention by academics and industry, because the toughness of materials often has a decisive influence on the application of products. A toughening agent is a substance that increases the flexibility of an adhesive film layer. Some thermosetting resin adhesives, such as epoxy resin, phenolic resin and unsaturated polyester resin adhesive, have low elongation and high brittleness after curing. When the bonding part is subjected to external force, it is easy to crack and expand rapidly. , causing the rubber layer to crack, not resistant to fatigue, can not be used as a structural bond. Mechanism of plastic toughening Different types of toughening agents have different toughening mechanisms. The liquid polysulfide rubber reacts with the epoxy resin to introduce a portion of the soft segment, which reduces the modulus of the epoxy resin and improves the toughness, while sacrificing heat resistance. As a toughening agent for epoxy resin, liquid nitrile rubber has almost no toughening effect at room temperature, and the bonding strength decreases. Only the medium-high temperature curing system has obvious toughening and bonding effects. The carboxyl-terminated liquid nitrile rubber toughened epoxy resin is compatible before curing, and is phase-separated after solidification to form an "island structure", which can absorb impact energy without substantially reducing heat resistance. T-99 multi-functional epoxy curing agent curing epoxy resin introduces a soft segment into the cross-linked structure, does not produce a phase-separated structure, and does not reduce heat resistance substantially while improving toughness. The thermoplastic resin continuously penetrates into the epoxy resin network to form a semi-interpenetrating network type polymer, resulting in an increase in toughness of the cured epoxy resin. The size of the nanoparticles is 1 to 100 nm, which has a very large specific surface area, and the surface atoms have extremely high unsaturation, so the surface activity is very large. The epoxy group forms a much larger interaction with the nanoparticles at the interface than the van der Waals force, which can induce microcracks and absorb energy. Nano-SiO2 and nano-clay can both cause silver streaks and terminate cracks. At the same time, the nanoparticles have a strong rigidity, and when the cracks expand, they encounter the orientation or deflection of the nanoparticles, and absorb energy to achieve the purpose of toughening. In addition, the nanoparticles have good compatibility with the resin, and the dispersion ability and absorption capacity of the matrix for impact energy are increased, resulting in an increase in toughness. What are the plastic toughening agents? How to divide? (1) How to divide the toughening agent commonly used in plastics 1. Rubber elastomer toughening: EPR (diethylene glycol), EPDM (ethylene propylene diacetate), butadiene rubber (BR), natural rubber (NR), isobutylene rubber (IBR), nitrile rubber (NBR), etc. Suitable for toughening modification of the plastic resin used; 2, thermoplastic elastomer toughening: SBS, SEBS, POE, TPO, TPV, etc.; used for polyolefin or non-polar resin toughening, for polyester, polyamide and other polymers containing polar functional groups toughen When a compatibilizer is added; 3. Core-shell copolymer and reactive terpolymer toughening: aCR (acrylate), MBS (methyl acrylate-butadiene-styrene copolymer), PTW (ethylene-butyl acrylate-methyl Glycidyl acrylate copolymer), E-Ma-GMa (ethylene-methyl acrylate-glycidyl methacrylate copolymer), etc.; used for engineering plastics and high temperature resistant polymer alloy toughening; 4. High toughness plastic blending and toughening: PP/Pa, PP/aBS, Pa/aBS, HIPS/PPO, PPS/Pa, PC/aBS, PC/PBT, etc.; polymer alloy technology is to prepare high toughness engineering plastics. Important route 5. Toughening by other means: toughening of nanoparticles (such as nano-CaCO3), sanding resin (DuPont metal ionomer) toughening, etc.; (2) In actual industrial production, the toughening of modified plastics is roughly divided into the following cases: 1. The synthetic resin itself has insufficient toughness, and it is necessary to improve the toughness to meet the use requirements, such as GPPS, homopolymer PP, etc.; 2, greatly improve the toughness of plastics, to achieve the requirements of super toughening, long-term use of low temperature environment, such as super tough nylon; 3. The resin is filled, flame retardant, etc., which causes the performance of the material to decrease. At this time, effective toughening must be carried out. General-purpose plastics are generally obtained by free radical addition polymerization. The main chain and side chain of the molecule do not contain polar groups. When toughening, rubber particles and elastomer particles can be added to obtain better toughening effect; Generally, it is obtained by condensation polymerization, and the side chain or terminal group of the molecular chain contains a polar group, and the toughness can be obtained by adding a functionalized rubber or elastomer particles toughness. In summary, plastic toughening is equally important for crystalline plastics and amorphous plastics, and the heat resistance of general-purpose plastics, engineering plastics, and special engineering plastics is gradually increasing, and the cost price is also rising, thus resisting toughening agents. Heat and aging resistance have put forward higher requirements, and it is also a big test for plastic modification and toughening technology. The most important and most important one is to maintain good compatibility with the matrix and components! Galvanized Mild Steel Link Chain Mild Steel Welded Straight Link Chain,Galvanised Steel Long Link Chain ,Mild Steel Galvanized Link Chain,Mild Steel Link Chain Guangdong Gongyou Lift Slings Machinery CO.,LTD , https://www.workmatehoist.com