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Preparation and Characteization of Polysiloxane-Polyacrylics-Polyurethane Tri-component Hybrid Latexes

Author: JiangXuBao
Tutor: KongXiangZheng;TanYeBang
School: Shandong University
Course: Polymer Chemistry and Physics
Keywords: Polyurethane modified Hydroxyl hydrocarbyl polysiloxane Acrylate Coupling agent Ternary complex emulsion
CLC: O631.3
Type: PhD thesis
Year: 2011
Downloads: 272
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Abstract


In this study, we polysiloxane and polyacrylate (PAC) will be used for both water-based polyurethane prepared by modifying both the three properties of novel ternary composites. A dual hydroxyalkyl hydrocarbyl capped and a molecular weight controllable polysiloxane, wherein the dual-hydroxyl group with an isocyanate monomer reaction modified polyurethane is prepared containing a polysiloxane segment; At the same time, for the current PAC changed the polyurethane (PU) using the coupling agent is a problem, i.e. monohydroxy coupling agent to the role of the end-capping of the polyurethane and polyhydroxy coupling agent resulting from the crosslinking reaction, etc., prepared in this paper, two new double bond-containing diol as a PAC and PU coupling agent, for the preparation of novel polysiloxane - Acrylic - Polyurethane ternary complex emulsion. Designed bishydroxy coupling agent is allyl glyceryl ether (AG) and methacrylic acid glycerides (GM), both respectively through the allyl glycidyl ether (AGE) and methyl glycidyl methacrylate (GMA ) is hydrolyzed under acidic conditions in the system. Nuclear Magnetic Resonance (NMR), infrared spectroscopy (FTIR), and gas chromatography of the resulting product, a detailed characterization. The GMA conversion rate of the reaction time and temperature. Experimental results show that with the extension of the hydrolysis time, the the GMA conversion rate gradually increased. Increase the reaction temperature of GMA significantly accelerated the rate of hydrolysis. In order to investigate the the bishydroxy coupling AG and GM with an isocyanate (NCO) and the reactivity of the acrylate monomer and monohydroxy acrylate, hydroxyethyl acrylate (HEA), compared to the coupling agent system, respectively, the above-mentioned three coupling agent with the NCO-terminated PU prepolymer PU molecular chain reaction to introduce a double bond, and then with the acrylate monomer by radical polymerization of the different types of coupled acrylate-modified polyurethane emulsion. Establish and validate the use of polyurethane and polyacrylate co-solvent such as tetrahydrofuran to the determination of the product of the method of the degree of crosslinking, from established theoretically calculated from the polymer cross-linking degree of the PU on the polyacrylate molecular chain graft rate. The results showed that the AG is used as a coupling agent, the allyl radical would be more stable and prone to self-inhibitor reaction, PU and PAC did not occur grafting reaction, while the coupling agent HEA and GM are available in PU and PAC between the establishment of the chemical bond. Changing the PU prepolymer with a coupling agent (GM and HEA) The reaction temperature for the reaction, the reaction temperature can make the NCO conversion rate and thereafter grafted with AC PU significantly increased. The use of HEA as a coupling agent when the latex particle slightly increased substantially independent the previous coupling agent and PU reaction effect of reaction temperature, the molecular weight of the resulting surgery terminal double bond-containing PU no significant change; but when using GM With GM and PU prepolymer reaction temperature increases, the composite emulsion latex particle size increased rapidly, significantly wider particle size distribution. Fixed reaction temperature at 75 ° C, when the OH / NCO lt; 1, regardless of which the coupling agent, the increase in the amount can make the graft ratio of the PU in the final emulsion polymer gradually increase, the OH / NCO GT; after PU grafting rate is not obvious. Urethane modified polysiloxane design has two important features, one of the polysiloxane molecular weight controllable; its end each containing a hydroxyalkyl group formed after the reaction with an isocyanate (NCO), is hydrolyzed higher stability of Si-CO. Through three-step reaction synthesis of a series of different molecular weight of bis (3 - (1 - methoxy-2 - hydroxy-propoxy) propyl) terminated poly siloxane (PMTS). First AGE tetramethyldisiloxane silicon hydride addition of ethylene alkyl-modified dimethylsiloxane (GTS), the then obtained after GTS methanolysis ends each containing a secondary hydroxyl group of dimethylsiloxane (MTS), and then MTS and octamethyl cyclotetrasiloxane (D4) equilibrium reaction, change MTS and D4 of the ratio obtained in a series of different molecular weight secondary hydroxyl capped silicone alkyl PMTS. The product was characterized by FTIR and 1H-NMR of the reaction of each step, respectively, by end-group analysis, gel permeation chromatography (GPC) and the 1H-NMR measurement of the molecular weight of the resulting silicone. Experimental results show that the molecular weight determined by end group analysis and 1H-NMR method consistent with the theoretical values, the result of the measurement by the GPC method in the same order of magnitude with the theoretical value, but large deviations. Polysiloxane and acrylic acid ester used for polyurethane-modified polysiloxane was prepared - Polyacrylate - polyurethane ternary complex emulsion. First with the introduction of isocyanate groups of isophorone diisocyanate with PMTS reaction is carried out in silicone molecular chain terminal with polypropylene glycol, dimethylol propionic acid, etc., then the reaction of the silicone-modified polyurethane (PSU) prepolymer, then GM (or HEA) introducing a double bond as the coupling agent in the PSU chain, and finally added to the acrylate monomer and a crosslinking agent after the emulsification, obtained by emulsion polymerization the coupling type silicone polyacrylate change polyurethane ternary complex emulsion. Under the same conditions, do not use a coupling agent to prepare the non-coupled ternary complex emulsion. The results showed that, regardless of whether the use of a coupling agent, the stability of the ternary complex emulsion significantly better than without PAC PSU binary emulsion. Coupled Emulsion for ternary complex emulsion and film the performance characterization results show that, compared with non-coupled Emulsion the coupled composite emulsion latex particle size is smaller and more uniform particle size distribution; the surface tension was significantly higher than the non-coupling type emulsion. Except in the case of higher molecular weight PMTS coupled latex film was not observed to a phase separation of the non-coupling type seen the use of the coupling agent for improving the hydrophobicity of the material and mechanical properties, a significant role. PMTS molecular weight and its amount of latex particle size, surface tension and viscosity of the emulsion is not obvious. PMTS molecular weight and its amount for the performance of the composite film, there is a limit. GM is used as a coupling agent, the molecular weight limit of about 2,000, the amount of upper limit of about 10 wt% of the PSU binary polymer the PMTS use this under mechanical and water resistance of the film can be improved significantly. HEA as the coupling agent, the molecular weight limit is also of 2000, the amount of not less than 5.0 wt%, the water resistance of the latex films have significantly improved.

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CLC: > Mathematical sciences and chemical > Chemistry > Polymer chemistry ( polymer ) > Polymer physics and physical chemistry of polymers > The chemical nature of polymers
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