Research On The Factors Affecting The Performance Of Temperature-Sensitive Rigid Polyurethane Foam

Polyurethane foam material occupies a large share in the polyurethane material market.According to different hardness and elasticity,polyurethane foam can be divided into soft foam,rigid foam,semi-rigid foam and so on.Among them,rigid foam PU is widely used in thermal insulation,transportation,oil exploration and other fields due to its high specific strength,low thermal conductivity and excellent mechanical properties.Temperature-sensitive polyurethane foam material(ie thermotropic shape memory polyurethane foam,SMPUF)is a microphase separated block copolymer composed of soft and hard segments with different glass transition temperatures,which can complete shape memory under thermal response process.Temperature-sensitive polyurethane materials have the characteristics of high deformation temperature design space,large deformation scale,high deformation retention rate,easy processing,etc.,and can be applied in many frontier fields.Therefore,exploring the factors that affect the performance of temperature-sensitive rigid polyurethane foam is of great significance to the improvement of the performance of rigid foam and the expansion of applications.The performance of polyurethane foam is closely related to factors such as soft segment,hard segment,cell structure,etc.This article starts from the above three main factors,and explores its effects on the mechanical properties of the material,cell structure,aging performance,glass transition temperature,and thermal weight loss.The influence law of temperature-sensitive performance,finally explored the influence of anti-aging additives on the aging performance of the material,and further improved the aging performance of the material.The relevant conclusions are as follows:(1)The foam prepared by PCL10 has the highest compressive strength and flexural strength,has the best cell structure,the cell shape coefficient is close to 1,the cell wall is thick,the pore size is moderate,the cell distribution is uniform,and the material has good heat-resistant air aging performance.Good deformation and temperature sensitivity.(2)With the gradual increase of the hard segment content,the compressive strength and bending strength of the material first increase and then decrease.When the hard segment content is 78% and 80%,the material has the highest mechanical strength.With the increase of the hard segment content,the cell pore diameter of the material first increases and then decreases,the pore shape coefficient first decreases and then increases,the cell wall thickness first increases and then decreases,and the glass transition temperature of the material gradually increases.The compressive strength after hot air aging increases first and then decreases.The higher the hard segment content of the material,the faster the shape recovery rate.When the ratio of BDO and DEG is2/3,the material has the highest compressive strength and bending strength,good cell structure,high glass transition temperature,high compressive strength after hot air aging,and good deformation temperature sensitivity.(3)The longer the mixing time of the materials,the smaller the pore diameter of the material,the smaller the pore shape coefficient,the closer to the ideal type of cells,and the greater the mechanical strength of the material.When the material mixing time is maintained at 35 s,the rigid polyurethane foam material has the highest compressive strength and bending strength.The material mixing time has no effect on the material shape fixation rate and the shape recovery rate.With the extension of the mixing time,the material shape recovery rate decreases.A6 foam stabilizer exhibits excellent foam stability,and can still keep the material with a larger cell structure under high-speed mixing.The polyurethane foam material prepared by it has the highest compressive strength and flexural strength,the highest compressive strength after aging,and the highest rate of shape recovery.(4)Antioxidant 1010 has the best anti-aging effect among the antioxidants used.The combined use of 1010 and 1680 further improves the aging performance of the material.When 1010/1680=1/3,the material has the best aging resistance and the best high-temperature weight loss performance.Adding carbodiimide anti-hydrolysis agent can effectively improve the seawater aging performance of the material.With the increase in the amount of anti-hydrolysis agent,the compressive strength of the material after seawater aging gradually increases.When the amount of anti-hydrolysis agent is1.25 to 1.5 phr,the compressive strength of the material after seawater aging reaches the maximum.