Synthesis and performance evaluation of polyurethane/silica hybrid resins

Abstract

Purpose -The aim of this paper is to synthesise polyester/silica hybrid resins and their hybrid polyurethanes via in situ (IS) and blending (BL) methods and to evaluate the effect of preparation method, interaction type and silica content on the physico-chemical and thermal properties of polyurethane/ silica (PU/Silica) hybrid coatings. Design/methodology/approach -Silica particle-containing silica sol was prepared according to Stö ber method using tetraethylorthosilicate as the precursor and then introduced into polyester matrix by in situ and direct blending method. The modified polyester/silica resin was further crosslinked with TMP-TDI adduct to synthesise PU/Silica hybrid coatings and studied for thermo-mechanical, physico-chemical properties. Findings -It was found IS polymerisation caused more polyester segments to chemically bond onto the surface of silica particles than BL process. Results also reveal that due to stronger interaction between silica particles and PU matrix, hybrid resins prepared by IS method confers better properties than BL method and exhibit optimal properties at the critical concentration of 8 wt% silica. Research limitations/implications -In the present study, silica particles are used to modify properties of polyurethane resins. Many other countless combinations in terms of inorganic filler or organic matrices can be explored to obtain a wide range of interesting properties and applications. Practical implications -The results obtained in this study will be extremely useful to enhance the understanding of this class of hybrid materials. Originality/value -Hybrid organic-inorganic networks offer a new area of material science that has extraordinary implications for developing novel materials that exhibit a diverse range of multi-functional properties.

Hybrid silica generated In situ in polyurethane‐based composites

“…Athawale and Kulkarni observed that the addition of silica precursors during the polymer synthesis generated stronger polymer‐silica interactions than those obtained when silica was added after the polymer synthesis. These stronger interactions may confer better properties . Similar behavior was reported by Kim et al, who observed an increase in hardness, initial modulus, and strength for tensile and compression loading.…”

Investigation into hybrid configuration in electrospun nafion/silica nanofiber

“…The peak placed at 950 cm À1 is related to the stretching vibration of the C-O-C group [31], which is observed in both nafion polymer and composite fiber, confirming silica hybridized with organics. In the case of the composite nanofiber mat, the broad band located at 1080, 790, 480 cm À1 are associated with Si-O-Si stretching vibration of SiO 2 [32]. In order to understand the configuration of composite nanofiber, the flame-treatment was carried out on composite nanofiber mat with directing heating by using the flame of alcohol lamp in air for 30 min and its IR curve is shown in Fig.…”

“…Obviously, the decomposition temperature of nafion polymer was dramatically improved due to the hybridization with silica nanofiber. The crucial factor for effecting the nafion decomposition may be related to the structural features of porous nanofiber mats, thermal insulation effect of silica and stronger chemical bonding between silanol group of silica sol and the sulfonic end groups of nafion [32]. The strong chemical bond of nafion/silica interface will contribute to faster energy transformation from polymer surface to silica matrix.…”

Properties of Vulcanized Polyisoprene Rubber Composites Filled with Opalized White Tuff and Precipitated Silica

“…The FTIR transmittance spectra of OWT and PSi are shown in Figure 1 and the assignment of the bands is shown in Table 3 . The characteristic bands almost at 1119, 792, and 466 cm −1 correspond to the stretching, bending and out of plane of Si–O bonds [ 18 , 19 ], respectively, for OWT, and 1088, 795, and 467 cm −1 for PSi. The position and the shape of the main Si–O vibration band at 1119 and 108 cm −1 show a stoichiometric silicon dioxide structure.…”

“…This means that OWT is poorly dispersed and interphase adhesion between NR and OWT is weak. Thus, free silica particles with relatively more unreacted hydroxyl groups easily promote aggregation through hydrogen bonding [ 19 ].…”