Vacuum treatment was used to coagulate natural latex. The effects of vacuum on physical and chemical properties

mechanical properties

thermal stability

crosslink density and processing properties of vacuum coagulated natural rubber (NR) were investigated

and compared with acid-coagulated natural rubber. The results show that the nitrogen content of vacuum coagulated NR is lower than that of acid coagulated NR. The nitrogen content gradually decreases with the increase of vacuum degree. The initial plastic value (

P

0

) and plastic retention rate (PRI) of vacuum coagulated NR are higher than those of acid coagulated NR. The ash content and Mooney viscosity are not much different. The mechanical properties of vacuum solidified NR are better than acid solidificatied NR

and the tensile strength of vulcanizate increases slightly with the increase of vacuum. As the degree of vacuum increases

the tensile strength of vulcanizates rises slowly. The vulcanization characteristics and thermal stability of NR are not much difference. The crosslinking density of vacuum solidified NR is larger than that of acid solidification

and its processing performance is better than that of acid-solidified rubber. In the range of vacuum

the comprehensive performance of NR is good when vacuum is —0.95MPa.