Though the non-rubber components have long been recognized to be a vital factor affecting the network of natural rubber (NR), the authentic role of non-rubber components on the network during accelerated storage has not been fully illuminated. This work attempts to clarify the impact of non-rubber components on the network for NR during accelerated storage. A natural network model for NR was proposed based on the gel content, crosslinking density, and the non-rubber components distribution for NR before and after centrifugation. Furthermore, the effect of non-rubber components on the network was investigated during accelerated storage. The results show that terminal crosslinking induced by non-rubber components and entanglements are primary factors affecting the network formation during accelerated storage. By applying the tube model to analyze the stress-strain curves of NR, we found that the contribution of the entanglements to the network formation is larger than that of terminal crosslinking during accelerated storage. The work highlights the role of non-rubber components on the network during accelerated storage, which is essential for understanding the storage hardening mechanism of NR.Keywords:natural rubber;non-rubber components;network;storage hardening
The quality stability of the natural rubber is a key point to its use in the industries and some special fields. However, due to storage hardening caused by the complicated molecular structure of natural rubber and non-rubber component, the quality uniformity is still not controlled in the nowadays rubber factory. In the previous research, storage hardening phenomena are extensively examined but the special mechanism is controversial and detail information is need to be further revealed. The dynamic evolution of accelerated storage properties and molecular structure of natural rubber have been investigated. The results show that △P increased slowly at first but then increased apparently and PRI has no direct relationship with △P. The storage time of 24 h is the critical storage period in which besides the △P and PRI, the P0, gel content and molecular weight also has obvious transformation. △P has a negative apparent correlation with ester content but protein content is relatively of no account in storage hardening process.
危险品化学品经营许可证（带存储）