Study On The System Design And Curing Kinetics Of Pultrusion Polyurethane Resin

The pultrusion molding process is an important molding method for preparing fiber-reinforced resin-based composite materials.A general-purpose resin matrix such as epoxy resin and unsaturated polyester resin can be used to prepare composite materials with excellent performance.In order to further improve the toughness and corrosion resistance of composite materials,and to increase the processing speed of composite materials,polyurethane resin matrix has been paid more and more attention.Polyurethane resin has the advantages of good impact toughness,fast reaction speed,large adjustable range of performance,and good adhesion to fibers.It has been widely used in fiber-reinforced resin-based composite materials.In this paper,a two-component polyurethane resin system suitable for pultrusion was studied.Through formula component compatibility testing,curing reaction characteristics study,and mechanical properties of polyurethane castings,polyurethane resin systems for pultrusion with excellent performance were obtained Compounded with glass fiber,glass fiber reinforced polyurethane pultrusion composite material was prepared,the influence of molding process on the performance of composite material was studied,and it had practical significance for processing and preparation of composite material.First,the formula of the polyurethane resin matrix is determined.In order to reduce the viscosity of the resin,the polyisocyanate PAPI and polypropylene glycol PPG were used as the main components.Through the compatibility test of the chain extender and the mechanical property test of the casting body,the formula principle of the multi-chain extender was determined.When the hydroxyl component is PPG When the content of MOCA and BDO is 30%,56%and 14%,the tensile strength of the resin casting body is 29.3MPa,the elongation at break is 10%,and the Shore D hardness is 93,which can meet the performance requirements of pultrusion resin matrix.In order to study the pultrusion process and resin reaction characteristics,the reaction kinetics of the formulation system was studied.Based on the Crane equation,the reaction order n was calculated.Based on the Flynn-Wall-Ozawa and Kissinge equations,E and A were analyzed and calculated.The kinetic model of the curing reaction of the polyurethane resin system was obtained.The reaction order was 0.84 and the reaction activation energy was 37KJ/mol;using T-β extrapolation method,the reaction start,peak top and end temperature were 40℃,120℃,208℃.Polyurethane resin has a low activation energy,can start the reaction at a lower temperature,and has a faster reaction speed,but the reaction termination temperature is higher,and a higher temperature post-curing process is required in the process.The glass fiber reinforced polyurethane composite material was prepared through a simulation process.Within a certain volume range,the volume fraction of glass fiber is proportional to the bending strength of the composite material.When the volume fraction of glass fiber rises to 72%,the performance of the composite material Best,the interface performance of resin and glass fiber is the best.