PODE柴油混合燃料对橡胶密封材料溶胀性的影响

摘要

为了解决聚甲氧基二甲醚(PODE)燃料在柴油机应用中的密封性问题,开展了PODE燃料对橡胶密封材料的溶胀性研究.制备了PODE体积配比分数为0%~40%的5种柴油混合燃料,通过浸泡法研究了PODE和添加剂对5种常用橡胶密封材料和一种特种材质橡胶溶胀性的影响规律.结果表明:橡胶在溶胀中,其质量和线径变化具有很好的一致性;随着浸泡,初期橡胶质量快速增大,然后维持稳定,最后缓慢下降.在相同PODE体积分数的混合燃料中,三元乙丙(EPDM)的溶胀一直最明显,其次依次为硅橡胶(QR)、氟橡胶(FKM)、丁腈橡胶(NBR)和氢化丁腈橡胶(HNBR);随着PODE的体积分数的增高,EPDM橡胶的溶胀逐渐减小,而其他橡胶的溶胀逐渐增加.乙醚和醇醚型添加剂可抑制橡胶溶胀,但幅度有限,在10%以内.采用全氟醚型橡胶可以有效解决PODE和柴油混合燃料的溶胀问题.%The swelling performance of rubbers in blends of diesel and polyoxymethylene dimethyl ethers (PODE) was studied to solve the sealing problem when using PODE in diesel engines. Five diesel-PODE blends with 0%~40% PODE were selected as fuel samples and five kinds of normal rubbers and a special rubber perfluorinated elastomers (FFKM) were selected as sealing materials. Immersion method was used to study the swelling performance. The results show that both mass and diameter of each rubber change in the same trend. The mass of rubbers increases quickly in the initial stage of immersion and then keep stable, and decreases slowly finally. Under the fuels with the same PODE blending ratio, the mass change ratio of ethylene propylene diene monomer (EPDM) is the biggest and then in sequence of silicon rubber (QR), fluororubber (FKM), nitrile-butadiene rubber (NBR) and hydrogenate nitrile (HNBR). The mass change ratio increases as PODE blending ratio rise for all normal rubbers except EPDM. The mass change ratio decreases as PODE blending ratio rises for EPDM. Diethyl-ether and alcohol-ether type additive could restrict the swelling a little, only lower than 10%. FFKM could solve the swelling problem of diesel-PODE blends well.