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This study demonstrates a new green rigid polyurethane (PU) based on modified palm oil (MPO) for marine buoy applications. The bio‐polyol based on palm oil was synthesized using hydrogen peroxide and formic acid. The foam formation was by kinetic foaming reaction. The MPO‐based PU foams made with increased water content had closed cells that grew larger with water content to provide a low‐density foam. The resistance to flammability of PU foam was improved by adding triphenyl phosphate (TPP). The PU foam with increased TPP content had enlarged cells, increased water absorption and decreased compressive strength. In addition, carbon black (CB)‐containing foam had uniform, large foam cells, comparatively high density, higher compressive strength, and low water absorption. Moreover, a high CB content gave shorter extinguishing time for PU foam. The PU foams were investigated for buoyancy and compared with a commercial PU foam buoy. The commercial buoy had lower density, providing better‐floating performance than PU foam. Interestingly, CB_8 had an elevated density, but low water absorption rate, similar to the commercial buoy PU foam. The investigations showed that the PU foam from MPO is eco‐friendly, and the buoyancy performance of that foam is improved on adding TPP or CB. [ABSTRACT FROM AUTHOR]

The incompatibility between hydrophilic silica and hydrophobic rubber is an important problem on using silica in nonpolar rubber. In this study, hydroxyl telechelic natural rubber (HTNR) that contains hydroxyl‐terminated groups was introduced into silica‐reinforced natural rubber (NR) in order to improve the bonding strength between rubber and silica. The properties of silica‐reinforced NR compounds and vulcanizates as a function of varying silica contents were evaluated at a fixed HTNR concentration at 8% wt/wt of silica content. The results show that the improvement of silica dispersion and decreasing of filler–filler interactions (Payne effect) were obtained in the NR compounds and vulcanizates with HTNR addition. The enhancements in tensile properties, crosslink density, abrasion resistance, heat build‐up, and thermal properties of the silica‐reinforced NR vulcanizates with added HTNR confirmed that HTNR performed good as interfacial modifier of silica. In the study, the optimum properties of silica‐reinforced NR vulcanizate were achieved at 30 phr silica with 2.4 phr HTNR. However, HTNR still showed poorer efficiency than the synergy between commercial silane coupling agent, bis [3‐(triethoxysilyl) propyl] tetrasulphide (TESPT) and diphenylguanidine (DPG) when used in silica‐reinforced NR vulcanizate. J. VINYL ADDIT. TECHNOL., 26:291–303, 2020. © 2019 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

ABSTRACT The effects of chain extender content (ethylene diamine, EDA) and NCO/OH ratio on the properties of natural rubber-based 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 Tg. The stress-strain curves clearly showed the change in WPU films from soft elastomeric materials to ductile and hard plastics. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42505. [ABSTRACT FROM AUTHOR]

A series of new waterborne polyurethanes (WPUs) was successfully prepared by prepolymer process from renewable source, hydroxytelechelic natural rubber (HTNR), with different amounts of DMPA (1.6-8.4 wt %), different molecular weights (1000-4000 g mol−1), and different levels of epoxide (0%-20%) of HTNR. It was found that the urethane conversions of prepolymer were over 80% as calculated by FTIR technique. The resulting HTNR2000-based WPUs exhibit a uniform particle size, which decreases from 420- to 83-nm diameters with an increase in the amount of DMPA from 2.9 to 6.6 wt %. The particle size also decreases with an increase of soft segment or with an increase of epoxide content. They are well stable more over 6 months and without a significant difference in particle size compared with starting of them. Chemical structure of WPU films was confirmed by FTIR, 1H-NMR, and 13C-NMR. Molecular weight and polydispersity were determined by SEC. In addition, thermal and water uptake properties were investigated. The experimental results reveal that the DMPA content, molecular weight of HTNR, and epoxide content play an important key role in water uptake and thermal properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]