Abstract

In order to investigate the effect of hydrophilicity and size of a filler on the reinforcement and supramolecular structure of polyurethane (PU) based composites, a sequence of polymer composites based upon oligomeric 4,4'-diphenylmethane diisocyanate (MDI) and propylene diol with molecular weight equal to 1000 were prepared via a simple in-situ method. Titanium (IV) dioxide (TO) was used as a microsized filler and an aerosol silica (AS) was used as a nanosized filler, both with hydrophilic surfaces. Carbon black (CB) was used as a microsized filler with a hydrophobic surface. The maximal degree of filling was varied from 5 wt% for AS, 25 wt% for CB, and up to 50 wt% for TO. It was shown that maximal reinforcement of the PU composites (up to one order of magnitude in improvement) could be obtained if the filler increases the microphase separation in the PU matrix. This effect was maximal for CB filler, although this filler was not active in the formation of hydrogen bonds. Thus, the neutral filler also changed the supramolecular structure of the polymer matrix. The strong reinforcement by the CB was connected with their nucleating ability, i.e. the possibility to produce a maximal number of rigid domains by CB/PU interactions in the PU matrix.

摘要

为了研究亲水性和填料尺寸对聚氨酯（PU）基复合材料的增强和超分子结构的影响，提出了一系列基于低聚4,4'-二苯基甲烷二异氰酸酯（MDI）和丙二醇与分子的聚合物复合材料的序列。通过简单的原位方法制备等于1000的重量。二氧化钛（TO）用作微米级填料，气溶胶二氧化硅（AS）用作纳米级填料，两者均具有亲水性表面。炭黑（CB）用作具有疏水表面的超细填料。最大填充度从AS的5 wt％，CB的25 wt％到TO的50 wt％不等。结果表明，如果填料增加了PU基体中的微相分离，则可以最大程度地增强PU复合材料（改善程度最高可达一个数量级）。尽管CB填料在氢键的形成中不起作用，但这种作用对CB填料最大。因此，中性填料也改变了聚合物基质的超分子结构。CB的强强化作用与它们的成核能力有关，即通过PU基质中CB / PU相互作用产生最大数量的刚性域的可能性。