The chain extender content and NCO/OH ratio flexibly tune the properties of natural rubber‐based waterborne polyurethanes

Abstract

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.

Synthesis and characterization of novel natural rubber based cationic waterborne polyurethane—Effect of emulsifier and diol class chain extender

“…HTNR with molecular weight of 2800 g mol −1 were synthesized by following the method of Saetung et al . and the 1 H nuclear magnetic resonance ( 1 H NMR) spectrum of HTNR is shown as previous result .…”

“…As well‐controlled method with high selectivity and repeatability, the chemical oxidation reaction was modified to prepare the NR telechelic substrate for this work. By our basic knowledge group, anionic WPU was successfully studied and the effects of emulsifier, molecular weight of HTNR, chain extender, and NCO index were reported . However, cWPU based on HTNR have been never reported in all data base.…”

Properties of waterborne polyurethane films: effects of blend formulation with hydroxyl telechelic natural rubber and modified rubber seed oils

“…All samples were synthesized by prepolymer mixing technique with the constant NCO/OH equivalent molar ratio 1:1, as described in prior work [11,13]. Briefly, the formulations for the waterborne polyurethane synthesis are shown in Table 2.…”

“…The chemical modifications of carbonyl end-groups and carbon-carbon double bonds at various ratios have also led to novel hydroxyl and amino telechelic cis-1,4-polyisoprenes. [8,18,19] In addition, our group has successfully prepared new natural rubber based polyurethane from these precursors, i.e., polyurethane films [8,9], biodegradable polyurethane [10], waterborne polyurethane [11,13] and flexible polyurethane foam [12].…”

“…However, the cost of fossil fuels, concerns about depleting the petroleum oil reserves, as well as environmental concerns about toxic wastes or global warming encourage prioritizing renewable raw materials [9]. For these reasons, much researcher attention and effort is devoted to the potential of renewable sources as raw materials of polymers, our focus here being on natural rubber [10][11][12][13][14] and vegetable oils [15][16][17].…”