Formulation Optimization And Compounding Modification Of Millable Polyurethane

Millable Polyurethane(MPU)is a special rubber material with excellent physical and mechanical properties,wear resistance,and dielectric resistance.Based on MPU,this topic explores the influence of the vulcanization system and reinforcement system of MPU on it,and also blends MPU with other materials for modification,and the performance changes of the blended rubber have been studied.The effect of the dosage of sulfur and carbon black on the performance of MPU was investigated using regression analysis design method.The experimental results show that the increase of both sulfur and carbon black dosage increased the crosslink density and vulcanization rate of MPU.With the increase of carbon black dosage,the hardness,100%modulus,wear volume and tear strength of MPU increased continuously,and the tensile strength,elongation at break and resilience decreased continuously.As the amount of sulfur increased,the hardness of MPU did not change significantly,the wear volume increased,the tear strength and elongation at break increased and then decreased,the tensile strength decreased slightly,and the resilience decreased.The mathematical model obtaine according to the regression analysis design method can more accurately reflect the relationship between the properties of MPU and the amount of sulfur and carbon black.In the peroxide vulcanization system,as the amount of peroxide vulcanizing agent BIPB increased,the crosslink density and vulcanization speed of MPU increased,while the mechanical properties of MPU showed a trend of rising and then decreasing.The addition of co-crosslinker can effectively improve the vulcanization efficiency of MPU,and also have an enhancing effect on the mechanical properties of MPU,while ZDMA has better reinforcement effect than TAIC.With the addition of flame retardant in the mating system,the hardness of MPU increased,the tensile strength decreased,the elongation at break decreased,the tear strength increased,the resilience decreased and the wear volume increased.Magnesium hydroxide as flame retardant has the best effect on improving the flame retardant performance of MPU,at which time the limiting oxygen index of MPU reached 33%,and the flame retardant effect of magnesium hydroxide-phosphorus flame retardant compound system is slightly better than that of halogen flame retardant,and the limiting oxygen index can reach 30%.The addition of carbon nanotubes(CNTs)can effectively improve the mechanical properties of MPU.The addition of two parts of CNTs can reduce the volume resistivity of MPU to 9.43×10~5Ω·cm,and the antistatic properties of MPU can be greatly improved.In the MPU/NBR blending system,the higher the content of acrylonitrile in NBR,the faster the vulcanization speed of the blends and the better the mechanical properties;as the percentage of NBR in the system increases,the vulcanization speed of the blends decreases,the tensile strength of the material keeps increasing,the tear strength first rises and then decreases,the 100%modulus first decreases and then rises,the elongation at break first rises and then decreases,and the hardness keeps decreasing.The effect of peroxide vulcanizing agent BIPB and crosslinker TAIC on the performance of MPU/NBR is investigated by regression analysis design method,and it is found that the performance of the blended rubber is excellent when the dosage of BIPB is 2phr and the dosage of TAIC is 2phr.The mathematical model obtained by the regression analysis design method can reflect the relationship between the properties of the blends and the dosages of BIPB and TAIC more accurately.the addition of CNTs and ZDMA improved the compatibility between MPU and NBR,increased the crosslinking density of MPU/NBR blends,accelerated the vulcanization speed,and significantly improved the mechanical properties of the materials.The addition of ACM and AEM can effectively improve the compatibility between MPU and NBR;the addition of ACM/AEM can promote the co-cure of MPU/NBR,improve the mechanical properties of the adhesive,improve the heat resistance and air aging resistance of the adhesive,and the AEM has a better effect on the properties of the adhesive.However,with the increase of TPU dosage,the mechanical properties of the material are improved;the order of adding the material will have a great influence on the properties of the material,and adding NBR with fast vulcanization rate first will make the material get better mechanical properties.When the amount of AEM is 20phr,the material has only one Tg.At this time the MPU/NBR/AEM has excellent mechanical properties and wear resistance,as well as excellent heat resistance and oxygen aging resistance,and has a wide range of application prospects.In MPU/AEM blending system,there is good compatibility between MPU and AEM and only one Tg.As the percentage of AEM in the system increases,the crosslink density of the material decreases,the vulcanization speed slows down,and the mechanical properties and wear resistance of the material also decrease as the percentage of AEM increases.The MPU/AEM developed in this experiment retains the excellent mechanical properties of MPU while integrating the excellent heat and oxygen aging properties of AEM,and can be applied in the preparation of wind power toothed synchronous belt,heat resistant conveyor belt and other special products,which is a new material with wide applicability.