Jopen Max, Paulus Michael, Sternemann Christian, Degen Patrick, Weberskirch Ralf
Carl Bechem GmbH, Weststraße 120, 58089 Hagen, Germany.
Fakultät Physik/DELTA, Technische Universität Dortmund, 44221 Dortmund, Germany.
Gels. 2023 Aug 29;9(9):696. doi: 10.3390/gels9090696.
High-performance greases typically consist of a base oil and polyurea as a thickener material. To date, few alternatives to polyureas have been investigated. Polyesters could be one such alternative; however, little is known about the gelation of such polyesters because, unlike polyureas, they cannot form hydrogen bonds between the polymer chains. Here, we present studies on the gel formation of a polyester based thickener poly(hexane dodecanoate) with 1-octanol endgroups in three different base oils, i.e., a mineral oil (Brightstock 150), a synthetic Polyalphaolefin (Spectrasyn 40) and castor oil (85 to 90 wt.% ricinoleic acid triglyceride). Small- and wide-angle X-ray scattering measurements indicate a strong interaction of the polyester with castor oil and an increase in the crystalline fraction, with an increasing polymer amount from 5 to 40 wt.%. Moreover, infrared analysis of the polyester in castor oil showed gel formation at a minimum concentration of 20 wt.%. The strong interaction of the polyester with castor oil compared to the other two base oils led to an increase in the yield point γ as a measure of the mechanical stability of the gel, which was determined to be 5.9% compared to 0.8% and 1.0% in Brightstock and Spectrasyn, respectively.
高性能润滑脂通常由基础油和作为增稠剂的聚脲组成。迄今为止，很少有人研究聚脲的替代物。聚酯可能是一种替代物；然而，对于此类聚酯的凝胶化了解甚少，因为与聚脲不同，它们在聚合物链之间无法形成氢键。在此，我们展示了关于一种带有1 - 辛醇端基的聚酯基增稠剂聚（己二酸十二烷酯）在三种不同基础油中凝胶形成的研究，这三种基础油分别是矿物油（光亮油150）、合成聚α - 烯烃（光谱合成油40）和蓖麻油（85至90重量%的蓖麻油酸甘油三酯）。小角和广角X射线散射测量表明聚酯与蓖麻油有强烈相互作用，并且随着聚合物含量从5重量%增加到40重量%，结晶部分增加。此外，对蓖麻油中聚酯的红外分析表明，在最低浓度为20重量%时形成凝胶。与其他两种基础油相比，聚酯与蓖麻油的强烈相互作用导致作为凝胶机械稳定性度量的屈服点γ增加，在光亮油和光谱合成油中测定的屈服点γ分别为0.8%和1.0%，而在蓖麻油中为5.9%。
