Study On Heat Resistance Modification Of Polyurethane Used For Elastic Fiber

Polyurethane elastic fiber is a kind of polyurethane elastomer.Because of its excellent mechanical properties and comfort property,it is often used in various fabrics.But with higher requirements of people on fabric color,the serious problem of high temperature dyeing spandex structure is outstanding which must be solved in order to meet market needs.In this paper,firstly,combining with the condition of industrial production needs,we will research process parameter,formulation design.Secondly,with the basis of reducing the industrial cost,we will use prepolymer method to explore the elastomeric materials which meet the high temperature resistance and good mechanical properties.Elastomer synthesis,hydrogen bonding,mechanical characterization,heat resistance and crystallinity will be researched.The experiments are as follows:First of all,Diphenyl-methane-diisocyanate and polytetramethylene ether glycol will be synthesized prepolymer.The effects of temperature and time on the cotent of NCO% will be explored in order to find the optimum reaction time and temperature of synthesize prepolymer.In the end,it was found that the best reaction condition was 80 min at 80?,which not only can satisfy the experimental requirements,but also can meet the need to reduce the industrial cost.Then,a series of different index of isocyanate prepolymer was synthesized from different proportion of diphenyl-methane-diisocyanate and polytetramethylene ether glycol(isocyanate index R=NCO/OH)based on the further conclusion experimental conditions.Then according to the stoichiometric ratio,synthetic elastomer was synthesized.Results show that the elastomer has the best mechanical properties when R is 1.6.But,the heat resistance of elastomers are little different.Then,polyurethane solution was synthesized by p-phenylenediamine based on R=1.6.The results showed that the viscosity of polyurethane solution is lost its liquidity with its not meeting the requirements of industrial production when we use p-phenylenediamine as chain extender,so that only using p-phenylenediamine to synthesize polyurethane solution did not satisfy the industrial requirements.Based on the above results,the prepolymer which R is 1.6 was synthesized.A series of synthetic elastomer samples was synthesized from either p-phenylenediamine mixture ethanediamine or 4,4'-Methylenedianiline mixture ethanediamine.Liquid viscosity,synthetic samples of hydrogen bonding,mechanical properties,heat resistance were research.Results showed: the viscosity of not only p-phenylenediamine / ethanediamine but also 4,4'-Methylenedianiline / ethanediamine to synthetize spandex synthetic solution can satisfy industrial production reproducibility.When p-phenylenediamine / ethylenediamine and 4,4'-Methylenedianiline / ethanediamine mole ratio is 1:2,the elastomer has the best thermal performance and good mechanical properties;p-phenylenediamine mixture ethanediamine as chain extender has better results than 4,4'-Methylenedianiline mixture ethanediamine.