What factors are related to the impact resistance of PVC resin?
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Some users have reported that products manufactured using a certain company’s PVC material have poor impact resistance, while using PVC material from another company meets the required standards. Is the impact resistance of PVC products truly related to the resin itself? Which indicators is it related to?
If it is a blank resin with no additives, I think it is still related to the process of preparing the resin spline; for example, bubble defects can occur if the resin has poor thermal stability. High moisture content in the resin can also cause bubbles to form during the plasticization process. Furthermore, under the same processing conditions, resins with a higher degree of plasticization also exhibit better impact resistance than those with a lower degree of plasticization. Some resins with good melt rheological properties also have better plasticization properties.
What I want to ask is, is impact resistance related to the degree of polymerization? Is it related to the molecular weight distribution?
I think the higher the degree of polymerization of PVC resin, the higher its glass transition temperature. Therefore, the more difficult it is to plasticize under the same processing conditions. PVC processing is not originally a process of complete plasticization. The higher the degree of plasticization, the better the mechanical properties. Similarly, resins with more branches are more difficult to plasticize than those with fewer branches at the same degree of polymerization.
Impact resistance is highly dependent on the type of resin; resins with a higher degree of polymerization exhibit better performance.
Reply to 5# Chen Gao: Based on actual testing results, the impact resistance of pure PVC (without impact modifiers) is almost the same for types 3, 5, and 7; therefore, I believe it has little to do with the degree of polymerization.
I believe it has nothing to do with dispersion and polymerization degree, but it is likely related to properties such as the resin’s absorption of plasticizers, which affects the post-processing performance of the resin.
I think it is related to the molecular weight distribution and to the monomer conversion rate
The higher the molecular weight of the resin, and if it can reach the molecular weight of rubber, then its impact resistance will definitely be excellent.