We investigate the one-pot synthesis of a new α,ω-bistrithiocarbonyl-end functionalized telechelic cis-1,4-polyisoprene (Pip) via metathesis degradation from natural rubber (NR) in the presence of the Grubbs second generation catalyst (GII) and a bistrithiocarbonyl-end functionalized olefin as a chain transfer agent (CTA). When the metathesis degradation of the NR of 2 × 106 g mol−1 molecular weight is performed in toluene at 25 °C using the ratio of [Ip]0/[GII]0/[CTA]0 = 100/1/1 (Ip = isoprene units), a cis-1,4-polyisoprene of 14 000 g mol−1 after 4 h is obtained. The functionality estimated by 1H NMR spectroscopy is equal to 1.5 ± 0.1. The structure of telechelic cis-1,4-polyisoprene was confirmed by combination of 1H NMR, 13C NMR spectroscopy and FTIR. The influence of the CTA concentration was investigated. It was found that using higher concentrations of CTA ([Ip]0/[GII]0/[CTA]0 of 100/1/2 and 100/1/5) lead to form a perfectly telechelic cis-1,4-polyisoprene with a functionality of 2 with no significant difference in values (approximately 6400 g mol−1) and in polydispersity indices (∼1.70). The new well-defined α,ω-bistrithiocarbonyl-end functionalized telechelic cis-1,4-polyisoprenes were used successfully as macromolecular chain transfer agents (macroCTAs) to mediate the RAFT polymerization of t-BA using AIBN as the initiator ([t-BA]0/[macroCTA]0/[AIBN]0 = 500/1/0.4) in toluene at 60 °C leading to well-defined P(t-BA)-b-PIp-b-P(t-BA) triblock copolymers.

The effects of chain extender content (ethylene diamine, EDA) and NCO/OH ratio on the properties of natural rubberbased waterborne polyurethanes (WPUs) were investigated experimentally. The particle size of WPU increased significantly with the NCO/OH ratio, in the presence of the EDA chain extender, while it was unaffected by the EDA content. The water uptake of WPU film increased with the EDA content, while the swelling in various solvents decreased. In a thermal analysis, the second decomposition stage of a WPU film increased with the EDA content and with the NCO/OH ratio that also positively affected the dynamic mechanical and mechanical properties. These factors in WPU films had no the effect on the T g . The stress-strain curves clearly showed the change in WPU films from soft elastomeric materials to ductile and hard plastics. V C 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42505.

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