Types and characteristics of toughening agents for nylon
DATE：2021/6/8 8:43:57 / READ： / SOURCE：This station
Types and characteristics of toughening agents for nylon
There are four kinds of toughening agents used for nylon toughening: rubber elastomer, thermoplastic elastomer, rigid organic copolymerInorganic rigid filler. However, not all elastomers are suitable for toughening nylon. Nylon is a kind of crystalline polymer with polarity. Generally speaking, elastomer with polarity is more suitable for nylon. Of course, it is also feasible to introduce polar groups in the macromolecular chain of non-polar elastomer by graft copolymerization. Single layer co extrusion casting film production line www.handern.com
Rubber elastomer rubber elastomer is an ideal toughening agent for polymer. The main reason is that rubber has high toughness, especially low T, which can endow plastics with excellent low temperature brittleness resistance. EPM, EPDM, NBR and SBR are used as toughening agents for nylon, SBS, SEBS, EVA and EAA are used as thermoplastic elastomers, and EPDM is used most. Rubber is used as toughening agent of nylon. It is better to colonize rubber before use. Only when the rubber is moderately crosslinked and its linear structure changes into network structure, can it have excellent modification effect. Thermoplastic elastomer thermoplastic elastomer is different from rubber in that it can be used directly without vulcanization and crosslinking. Its elasticity is close to that of rubber, and its thermoplastic elastomer is copolymer or graft copolymer. SBS has high elasticity due to the presence of butadiene in macromolecule. The elasticity of SBS varies with the content of butadiene. SEBS is a hydrogenated product of SBS. The biggest characteristic of SEBS is that its weatherability is stronger than that of SRS. There are some differences between thermoplastic nylon and rubber milk nylon in properties. The former has higher bending strength and other rigidity properties than the latter. Single layer co extrusion casting film production line www.handern.com
The research of rigid organic polymer toughening is far less extensive and in-depth than that of elastomer. There are not many kinds of organic quotient molecules, such as liquid polymer, which play an increasing role in nylon. However, from the principle of incremental control,
The home compound with lower TG than nylon has a certain shear increasing effect on nylon, such as pppe, ABS, etc
The closing effect is not as good as that of elastomer. Rigid inorganic particles, when the particle size of inorganic filler reaches nanometer scale, have certain toughening effect, such as C: CO, talc, montmorillonite, shoe limestone, etc. the property corrector has certain toughening effect on nylon, which can improve the properties of nylon foot, but not as good as the outer body. In order to obtain toughened nylon with good processability and high rigidity, it is necessary to use composite toughening agent or toughening reinforcing composite technology. Single layer co extrusion casting film production line www.handern.com
The key technology in the preparation of toughened nylon is to increase the compatibility between elastomer and nylon, improve the adhesion between components, and improve the properties of interphase interface layer, so as to improve the initial effect. The following technologies are introduced: (1) reactive compatibilization technology. The so-called reactive compatibilization is the introduction of polar compounds which can react with polar groups in nylon macromolecular chain. To form a partial chemical bond between the elastomer and nylon. There are many carbon carbon double bonds in the elastomer macromolecules. Maleic anhydride, acrylic acid and other monomers are used to graft the elastomer. The graft copolymer elastomer prepared by grafting MAH onto EPDM has dianhydride functional group. When melt blending with PA6, the anhydride functional group can easily react with the terminal amino group of PA6 to form chemical bond. Due to the formation of chemical bond, the interfacial compatibility between the elastomer and PA6 is significantly improved, and the notched impact strength of the toughened PA6 reaches 1000 J / m（ 2) "Shell core" copolymer toughening method "core" copolymer is a kind of CO valent polymer batch culture system with cross-linked elastomer as core and polymer with higher glass transition temperature as shell, which is not affected by blending processing conditions（ 3) Dynamic vulcanization technology and dynamic vulcanization technology of blending thermoplastic elastomer the so-called dynamic vulcanization refers to "in situ vulcanization" when rubber and thermoplastic resin are melt blended. In fact, the vulcanization process is the crosslinking process. As we all know, rubber processing must be vulcanized, so that the linear structure into a three-dimensional or network structure in order to have a certain strength and hardness, ordinary vulcanized rubber rely on the crosslinking network formed during vulcanization to provide strength, it is thermosetting; In the process of dynamic vulcanization, due to the high shear stress, the rubber strands are dispersed in the carrier resin, the crosslinked rubber micro area mainly provides the elasticity of the blend, and the resin provides the plastic fluidity at the melting temperature. The dynamic vulcanization technology provides a new type of thermoplastic elastomer - blending thermoplastic elastomer. Single layer co extrusion casting film production line www.handern.com
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