English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The effect of fatty acid linked to cis-1,4 polyisoprene on the crystallization of polymer chain was investigated by differential scanning calorimetry (DSC) and dilatometry at -25t. Synthetic cis-1,4 polyisoprene (IR) was esterified with stearic acid selectively at 3,4 isoprene units after introduction of OH group by hydroboration (IR-C 18). The rate of crystallization of IR-C 18 was increased by the addition of saturated fatty acids. The addition of methyl linoleate promoted the crystallization of IR-C 18, whereas it suppressed the crystallization of IR. This was explained to be due to a synergistic effect of mixed and linked fatty acids on the crystallization of IR. Stearic acid was introduced into natural rubber (NR) by esterification after purification of NR by deproteinization followed by acetone extraction and transesterification with NaOCH3. The content of stearic acid in the esterified NR (DPNR-C 18) was about 1/2 compared to the ester content in untreated NR. The rate of crystallization of DPNR-C 18 was similar to that of DPNR-TE and was not increased by the addition of methyl linoleate. Precooling of the rubber at 0, 10 and 30t before crystallization at -25t resulted in a significant difference in the crystallization rate between untreated NR, DPNR-TE and DPNR-C 18, where the crystallization of only untreated NR was promoted by precooling. This demonstrates the presence of a critical concentration of linked fatty acid on the crystallization of NR, at which the synergistic effect was promoted with mixed fatty acids. (Received on July 9, 1998) Key Word : Natural Rubber, cis-1,4 Polyisoprene, Linked Fatty Acids, Hydroboration, Transesterification, Crystallization Behavior, Rate of Cryytallization

Crystallization behavior of natural rubber. Part 1. Effect of mixed fatty acid on the crystallization of cis-1,4 polyisoprene.