Understand the toughness, rigidity and impact resistance of plastics in one article

"Rigidity" refers to the amount of force required when an object undergoes unit deformation;

"Flexibility" refers to the amount of deformation of an object under unit force.

The greater the "rigidity", the less likely to be deformed; the greater the "flexibility", the easier it is to deform.

Materials with good toughness are softer, with higher tensile elongation at break and higher impact strength, but lower hardness, tensile strength and tensile elastic modulus.

It can be seen from the above description that stiffness and toughness are in opposition, but for modified plastic products, the two are interdependent. For example, after using glass fiber reinforced plastic, while its rigidity increases, both tensile strength and impact strength may increase.

How to improve the toughness of plastics It is found through testing of plastic products that increasing the toughness of the matrix resin is beneficial to improving the toughening effect of toughened plastics. There are many ways to toughen, such as increasing the molecular weight of the matrix resin to narrow the molecular weight distribution, or controlling the crystallinity and crystallinity, crystal size and crystal form to improve toughness.

How to distinguish the commonly used tougheners for plastics? Rubber elastomer toughened EPR (ethylene propylene diene monomer), EPDM (ethylene propylene diene monomer), butadiene rubber (BR), natural rubber (NR), isobutylene rubber (IBR), butadiene rubber Nitrile rubber (NBR), etc.; suitable for the toughening modification of all plastic resins; thermoplastic elastomer toughening SBS, SEBS, POE, TPO, TPV, etc.; mostly used for polyolefin or non-polar resin toughening, for polyester When toughening polymers containing polar functional groups, such as polyamides and polyamides, compatibilizers must be added; core-shell copolymers and reactive terpolymers are toughened with ACR (acrylates), MBS (methyl acrylate-butyl Diene-styrene copolymer), PTW (ethylene-butyl acrylate-glycidyl methacrylate copolymer), E-MA-GMA (ethylene-methyl acrylate-glycidyl methacrylate copolymer), etc.; It is mostly used for toughening engineering plastics and high temperature resistant polymer alloys; high toughness plastic blending toughening PP/PA, PP/ABS, PA/ABS, HIPS/PPO, PPS/PA, PC/ABS, PC/PBT, etc.; high Molecular alloy technology is an important way to prepare high-toughness engineering plastics; other ways to toughen nanoparticles (such as nano-CaCO3), sarin resin (DuPont metal ionomer) toughness, etc. Polyolefin POE, EPDM, EVA, SBS, SEBS, EPR, NR PVC TPU, CPE, ACR, NBR, MBS, NBR ABS CPE, ACR, high rubber powder PC MBS, silicone-containing acrylate rubber PBT/ PET POE-GMA, E-MA-GMA, EPDM-GMA, core-shell copolymers, ionomer PA NBR, EPDM, SBS, SEBS and POE and their corresponding graft copolymers, core-shell copolymers, UHMWPE, TPAE PPO HIPS, SEBS-MA, POE-MA PPS SEBS-MA, E-MA-GMA, HDPE-MA, TLCP, PTFE, ionomers. In principle, the essence of toughening can be said to be compatibilization. If the toughening agent is regarded as a kind of polymer, the principle of compatibilization can be extended to all polymer blends. When preparing useful polymer blends in industry, reactive compatibilization is a technology that we must use. Therefore, the toughening agent has a different meaning, and it is precisely this that has the "toughening compatibilizer ", the image title of "interface emulsifier"!

How to improve impact resistance As engineering plastics, we hope it has good toughness and rigidity at the same time. When improving the toughness of the material, we should also try to increase the rigidity. In general, adding inorganic fillers can increase rigidity. But the most effective method is to combine the toughening of the elastomer and the reinforcement of the filler. Poor impact resistance is a performance defect of some important plastics in the industry. Such as PVC, PS, PP, etc., especially at low temperature due to low impact resistance, which limits their application. However, in thermoplastics, their impact resistance can be greatly improved by adding "impact modifiers". Varieties of impact modifiers: ACR-acrylate resin, MBS-methyl methacrylate-butadiene-styrene copolymer, CPE-chlorinated polyethylene, ABS, EVA, EPT-terminated Acrylic rubber and so on.

 From the perspective of the modification effect of plastic products, ACR is the category with the best overall performance; MBS is an important impact modifier for transparent products and occupies an important position in the global impact modifier market. Although impact modifiers can increase impact strength, they have an adverse effect on other mechanical strengths. If MBS is added to PVC, the tensile strength and bending strength are reduced. The addition of ACR will also reduce the tensile strength, hardness and Vicat heat resistance of HPVC-high molecular weight PVC. The addition of CPE also reduces the tensile strength, flexural strength and Vicat softening point of the blend.

Therefore, when using impact modifiers, other properties must be taken into consideration and be considered comprehensively. To determine the appropriate dosage.