Effects of latex maturation time on composition and properties of natural rubber.

The fresh latex was preserved using the composite preservative HY/NH3 for 1 ~ 5 d, regular sampling and solidification to prepare raw rubber. A sample with a latex maturation time of 1 d was used as a control sample to investigate the effect of maturation time of fresh latex on the composition and prop-erties of natural rubber. The natural rubber was characterised using instruments such as infrared spectros-copy, nuclear magnetic resonance crosslink density and tensile testing machines, respectively. The results showed that the maturation of fresh latex could reduce the content of impurities, ash and volatiles in raw rubber sheets, and improve the plasticity retention index and cross-link density. The scorch time, positive vulcanization time, torque difference of compounded rubber and tensile strength, tear strength, constant tensile stress of vulcanized rubber were all improved. The natural rubber prepared from the fresh latex for 3 d of maturation had the best overall performance, and the tensile strength and tear strength of vulcanized rubber reached were up to 20.47 MPa and 30.38 kN/m, respectively, an increase of 3.5% and 7.0% compared to the control sample. [ABSTRACT FROM AUTHOR]