Study On Preparation Of Modified Waterborne Polyurethane Emulsion Sizing Agent And Application On Carbon Fiber

Carbon fiber is widely used as a reinforcement for composite materials because of its excellent properties such as high temperature resistance,corrosion resistance,low density,low expansion coefficient,high specific modulus,and high specific strength.The sizing agent is an important part of the carbon fiber production process.As a carbon fiber sizing agent,waterborne polyurethane has the advantages of good abrasion resistance,strong adhesion,high mechanical strength,excellent corrosion resistance,outstanding resin compatibility,and good high and low temperature resistance.It has a wide application prospect and greater research value.This article uses isophorone diisocyanate,poly-1,4-butanediol adipate,2,2-dimethylolbutanoic acid,1,4-butanediol,triethylamine,etc.as raw materials,with Dibutyltin dilaurate was used as a catalyst to prepare a self-emulsifying polyester waterborne polyurethane sizing agent.Through orthogonal experiments,the optimal synthesis process was explored using the average particle size and distribution of the emulsion and the stability of the emulsion as the evaluation criteria,and the particle size of the emulsion was obtained.Significant influencing factor-the percentage of the hydrophilic chain extender in the prepolymer.Taking the percentage of the hydrophilic chain extender in the prepolymer as the starting point,through the emulsion particle size and stability analysis,Fourier transform infrared spectroscopy analysis,film water absorption analysis,X-ray photoelectron spectroscopy analysis,carbon fiber sizing Quantitative analysis,field emission scanning electron microscope analysis,and micro-debonding experiment analysis have studied the properties of sizing agent emulsions with different hydrophilic chain extender contents and the properties of carbon fiber after sizing.After comprehensive comparison,the performance of self-emulsifying polyester waterborne polyurethane sizing agent is determined The best synthesis process conditions are:R value 2.0,DMBA percentage content 5%,neutralization degree 100%,reaction temperature 80?,the interfacial shear strength of carbon fiber sizing by this process is 11.8%higher than that of unsizing carbon fiber.Research on the modification of waterborne polyurethane based on the optimal synthesis process conditions.Polytetrahydrofurandiol was added in the synthesis stage of the prepolymer,and the ratio of the amount of polyester diol to polyether diol was designed to be 3:1,1:1,1:3 three formulations,prepared water-based polyurethane emulsion and configured into a sizing agent,the performance of the sizing agent and the performance of the carbon fiber after sizing were analyzed and characterized.The analysis results showed that the introduction of polyether segments can reduce the water The water absorption of polyurethane film,but it will also reduce the initial viscosity of waterborne polyurethane to a certain extent,and increase the particle size of the emulsion.In the carbon fiber sizing with three different types of alcohol ratio polyurethane sizing agent,the interfacial shear strength The highest is 10.13%higher than the unsizing carbon fiber,which is lower than the result of using polyester glycol alone as the raw material.3-Aminopropyltriethoxysilane was introduced into the polyurethane prepolymer,and the effect of silane addition amount on the properties of polyester/polyether composite waterborne polyurethane sizing agent and sizing carbon fiber was studied.The results show that the addition of silane will reduce the average particle size of the waterborne polyurethane emulsion,and can also increase the initial viscosity of the waterborne polyurethane sizing agent.After sizing,the interfacial shear strength of carbon fibers has been further improved.When the silane addition amount is 3%,the change The interfacial shear strength of carbon fiber sizing with waterborne polyurethane is 18.29%higher than that of unsizing carbon fiber.The water absorption rate of the silane-modified waterborne polyurethane sizing agent has been significantly reduced,and it can be used as a carbon fiber sizing agent.