Because nylon is a polar crystalline polymer, not all elastomers can be used to strengthen it. Polar elastomers are often more suited for toughening nylon. Of course, nylon may also be made more durable by adding polar groups to the macromolecular chains of non-polar elastomers by graft copolymerization.
The following categories serve as general classifications for nylon tougheners:
elastomer of rubber
The best polymer tougheners are rubber elastomers. The primary explanation is that rubber may provide plastics good resistance to low temperature brittleness because it has a high modulus of elasticity and a low glass transition temperature. There are several types of rubber that may be used to toughen nylon, including EPDM, ethylene propylene, nitrile, styrene butadiene, and butadiene rubber. EPDM is the most often used.
It is ideal to vulcanize rubber before usage as a toughening agent for nylon. This involves making the rubber considerably cross-linked so that it transforms from a linear structure to a network structure, giving it a specific strength and hardness, and allowing hardened nylon to play a role. appropriate impact of toughening.
thermally flexible rubber
The thermoplastic elastomer differs from rubber in that toughening may be accomplished without vulcanization or crosslinking. Its suppleness is similar to rubber’s. Copolymerized polymers, also known as graft copolymers, are thermoplastic elastomers.
Due to the presence of butadiene in the macromolecule, SBS (styrene/butadiene copolymer) endows SBS with high elasticity. The elasticity of SBS will vary with varied butadiene concentration.
A hydrogenated version of SBS is SEBS. The main benefit of this product is that it is more resistant to weather than SBS.
To create thermoplastic elastomers, all of the aforementioned monomers are copolymerized. Additionally, the thermoplastic elastomer created by twin-screw blending reaction extrusion with rubber as the major component, blended with various plastics, and strengthened by a crosslinking agent, such as EPDM/PP, EPDM/PE, etc., may also be used as toughening.
The performance of rubber toughened nylon and thermoplastic elastomer toughened nylon varies to some extent. Compared to rubber, thermoplastic elastomers perform better in terms of bending strength.
inflexible organic polymer
Compared to elastomers, stiff organic particle toughening has received far less investigation. Liquid crystal polymers are one of the few organic stiff polymer forms that can toughen nylon. However, according to the toughening principle, nylon is somewhat toughened by polymers like PP, PE, ABS, etc. that have a lower glass transition temperature than nylon. These polymers are not as resilient as elastomers, though.
rigid inorganic material
This kind of substance is an inorganic filler, and it has a particular toughening effect when the particle size of the inorganic filler reaches a nanoscale size. like talc, montmorillonite, wollastonite, CaCO3, etc.
The stiffness of nylon can be improved by hard particles, however this effect is not as strong as the toughening effect of elastomers. Composite toughening agents or toughening and strengthening composite technology can be used to produce nylon that has been toughened and has good toughness and high stiffness.
Additionally, whiskers also provide nylon a slight toughening effect.
metallic polyolefin
Because there are no double bonds in the macromolecular chain, thermoplastic elastomers with good elasticity and weather resistance include the copolymer of ethylene and octene (POE). POE was first primarily employed to toughen polyolefins, however after being grafted with reactive monomers like maleic anhydride, POE exhibits strong compatibility with nylon. The best toughening agent for PA6 and PA66 is POE hardened PA6, which not only has great impact resistance at low temperatures (-40°C), but also strong impact strength at room temperature.
copolymer core-shell
A flexible molecule serves as the center of the so-called core-shell copolymer, while a stiff molecule serves as the shell structure. On nylon, this copolymer has a significant toughening effect.
