“三源一体”皮革基膨胀阻燃剂的制备及其在热塑性聚氨酯弹性体中的应用研究

Preparation of“Three Sources in One”Leather-based Intumescent Flame Retardant and Its Application in Thermoplastic Polyurethane Elastomer

将皮革固体废弃物(LW)直接回收成为高附加值的产品一直是困扰制革工业的难题.本文工作以富含氮/碳元素的LW作为炭源/气源,聚磷酸铵(APP)为酸源,通过静电作用在水溶液中制备了“三源一体”皮革基膨胀阻燃剂PA@LW@APP,并通过熔融共混方式将其引入到热塑性聚氨酯弹性体(TPU)中.研究发现,当添加量为5 wt%时,TPU5便能达到UL-94 V-0级.在锥形量热测试中,阻燃TPU能够形成阻隔外部火源和可燃气体的膨胀炭层,表现出优异的抑热、抑烟及成炭能力.含有15 wt%PA@LW@APP的阻燃TPU的峰值热释放速率、总热释放量和总烟释放量相比于纯TPU分别降低了71.1%、36.0%和51.4%.另外,PA@LW@APP的包覆型结构使得它在TPU基材中分散良好,不易团聚,所制备的阻燃TPU均保持了良好的拉伸韧性.本工作通过绿色简单的方法不仅实现了皮革废弃物的高值化利用,而且还赋予了TPU优异的阻燃性能.

Direct recycling of leather waste(LW)into high value-added products has always been a challenge for the leather industry.In this study,a“three sources in one”leather-based intumescent flame retardant(PA@LW@APP)was prepared in aqueous solution by electrostatic interaction,using LW rich in nitrogen/carbon elements as a carbon/gas source and ammonium polyphosphate(APP)as an acid source.Then PA@LW@APP was introduced into thermoplastic polyurethane elastomer(TPU)by melt blending.It was found that when the addition content of PA@LW@APP is 5 wt%,TPU5 can achieve UL-94 V-0 rating.The flame retardant TPU forms an intumescent char layer during cone test that blocked the external fire source and combustible gas,showing excellent heat suppression,smoke suppression and char-forming abilities.Compared with pure TPU,the peak heat release rate(pHRR),total heat release(THR)and total smoke production(TSP)of flame retardant TPU containing 15 wt%PA@LW@APP were reduced by 71.1%,36.0%and 51.4%,respectively.In addition,the encapsulated structure of PA@LW@APP made it well dispersed in the TPU substrate and not easy to agglomerate,and the flame retardant TPU maintained good tensile toughness.This work not only realizes the high-value recycling of leather waste through a green and simple method,while also giving TPU excellent flame retardant properties.