Toughening agent for nylon and its characteristics

Nylon is a polar crystalline polymer, and not all elastomers are suitable for nylon toughening. In general, polar elastomers are more suitable for nylon toughening. Naturally, according to thermally polymerized copolymers, optically active functional groups in non-polar elastomeric biomacromolecules can also be used to toughen nylon.

1. Rubber elastomer.

Rubber elastomers are ideal toughening agents for polymers. Mainly, rubber has high tensile strength and low glass transition temperature, which can give plastic high-quality ultra-low temperature ductility. As the toughening raw materials of nylon, there are EPDM rubber, ethylene rubber, nitrile rubber, styrene butadiene rubber, butadiene rubber, etc. The most common is EPDM.

As a toughening agent for nylon, it is better to develop vulcanized rubber before application, that is, to make the rubber properly chemically cross-linked, so that it can change from a linear structure to a porous structure, so that it has a certain compressive strength and strength, and toughens nylon. Only then can the actual effect of toughening be exerted.

2. Thermoplastic elastomer.

Thermoplastic elastomers differ from rubber in that they can be immediately applied for toughening without the need for chemical crosslinking of vulcanized rubber. Its ductility is close to that of rubber. Thermoplastic elastomers are copolymer polymer materials or thermally polymerized copolymers. PE wax for SBS (butadiene/butadiene copolymer) has high ductility due to the appearance of butadiene in biological macromolecules, and the elasticity of SBS will also be different if the butadiene composition is different. This degradation includes reactions such as depolymerization, random chain scission, removal of side groups and low molecular weights.

SEBS is a commodity obtained by esterification of SBS, and the highest characteristic of this equipment is that it is more resistant to aging than SBS.

All of the above are single copolymerized into thermoplastic elastomer. In addition, with rubber as the main body, some plastics in compound fertilizer, under the effect of coupling agent, the thermoplastic elastomer produced by single-screw blending reflection extrusion can also be used for toughening applications, such as EPDM/ PP, EPDM/PE, etc.

Thermoplastic elastomer toughened nylon and rubber toughened nylon have certain differences in properties. The flexural strength properties of thermoplastic elastomer toughened are higher than those of rubber toughened.

3. Rigid organic polymers.

The scientific research on the toughening of rigid organic chemical particles is not as good as the scientific research on elastomers. There are not many types of organic chemical rigid polymer materials that can toughen nylon, such as liquid crystal polymers. However, from the basic principle of toughening, polymers with a lower glass transition temperature than nylon have a certain practical effect of toughening on nylon, such as PP, PE, ABS, etc. However, the actual toughening effect of such polymers is not as good as that of elastomers.

4. No rigid material.

These raw materials are actually inorganic fillers. When the particle size of inorganic fillers reaches nanometer size, it has a certain toughening effect. Such as CaCO3, light calcium powder, montmorillon, silica sand, etc.

Stiffness particles have a certain practical effect on nylon toughening, which can improve the stiffness of nylon, but it is not as tough as elastomers. To obtain toughened nylon with good ductility and high stiffness, composite toughening agents or toughening can be used to improve composite technology.

In addition, the whiskers also have a certain toughening effect on nylon.

5. Metallocene polyolefins.

Attributable to thermoplastic elastomers, such as the copolymer of butadiene and octene (POE), it has good ductility, and at the same time, because there is no hydrocarbon group in the biological macromolecular chain, it has excellent aging resistance. At first, POE was mainly suitable for the toughening of isoprene rubber, but POE has good compatibility with nylon after being polymerized by reactive single heat such as maleic anhydride. POE toughened PA6 not only has a high impact on compressive strength at room temperature, but also has good impact resistance properties at lower temperatures (-40°C), making it the best toughening agent for PA6 and PA66.

6. Core-shell copolymer.

A core-shell copolymer is a copolymer with a soft molecular structure as the core and a rigid molecular structure as the shell. This kind of copolymer has strong toughening effect on nylon.