Control Of Intermittent Foaming Performance Of Poluether Block Polyamide Elastomer

Polyether block polyamide(PEBAX)is a new type of thermoplastic elastomer whose molecular chain is composed of hard and soft segments.PEBAX copolymer has excellent mechanical properties,anti-aging and chemical resistance,etc.,from the early replacement of chemical cross-linked rubber to now widely used in various fields,such as high permeability materials,golf cores,etc.,while PEBAX foam materials It has also been developed for use in footwear,sports and leisure,clothing,medical equipment and other fields.However,the production of PEBAX is expensive,the foamability of the pure material is poor,and the required foaming conditions are harsh.These problems limit the application of PEBAX foam materials.This article mainly studies the PEBAX-4033 material composed of nylon 12 and polytetrahydrofuran.The effect of different holding temperatures on the thermal properties of the material is tested by a differential scanning calorimeter,and the effect of different holding times is compared.The sheetlike samples were subjected to intermittent foaming experiments to study the foaming properties of the untreated pure materials,and to determine the foaming temperature zone and foaming temperature.The results show that it is difficult to obtain good foamed products by directly foaming pure materials.The best foaming temperature of pure materials is within 160-170?,and the highest foaming ratio obtained is 7.91 times and the cell density It is 3.62×106/cm3.By performing differential scanning calorimetry and dynamic rheological tests on the material,the foaming process is changed,and the melting and cooling foaming can obtain products with more uniform cell structure and higher foaming ratio,and also improve the shortcomings of narrow foaming temperature zone.Through melt processing to change the reorganization and distribution of the hard segments of the material,combined with the internal mixing torque curve,the dynamic rheological test studied the effect of melt processing on the thermal and rheological properties of the material,and combined the intermittent foaming experiment to study the effect of melt processing on the hair Improvement of foam performance.The effect of adding two different epoxy polymerized chain extenders KLE4370 and KL-E4370B on the chain extension of PEBAX was studied,and the effect of the addition of chain extenders on the thermal properties and rheological properties was studied.The foaming samples obtained by foaming were tested and characterized,and the foaming performance of the samples obtained by adding different types and different content of chain extenders were compared.The results show that the two chain extenders have excellent chain extension modification effects,and both can significantly increase the viscosity of PEBAX and increase the molecular weight.The obtained foamed samples have better cell morphology.The content of KL-E4370 is 2.0%.When the temperature is 160?,the foaming sample with the expansion ratio of 14.17 times can be obtained,the cell density is 5.23 × 107/cm3,the cell diameter is 86.79um,and the material modified with 1.5%KL-E4370B chain extender can be used.At 165?,a foamed sample with a foaming ratio of 15.69 times,a cell diameter of 73.79um,and a cell density of 7.01×107/cm3 is obtained,and the sample does not shrink and has a smooth surface.