Effect of N-heterocyclic carbenes-Pt catalytic system and crosslinking networks on the pyrolytic behavior of liquid silicone rubber

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability Pub Date : 2024-09-01 DOI:10.1016/j.polymdegradstab.2024.110986

Dingsong Wang , Wanyan Li , Jingjing Qin , Youwei Zhu , Liyan Liang , Changan Xu

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引用次数: 0

Abstract

Liquid silicone rubber (LSR) exhibits excellent thermal stability and has been selected for use in a variety of applications where thermal stability, chemical resistance and fire-retardant are required. The enhancement of the organic-to-inorganic conversion of LSR to improve their flame-retardant properties represents a significant area of research. The thermal stability of the platinum catalysts and the crosslinked network structure of the LSR have a considerable influence on the organic-to-organic conversion behavior of LSR. The present study demonstrates the efficacy of N-heterocyclic carbene (NHC) ligand-modified Karstedt's catalysts as catalysts for the curing of LSR by hydrosilylation at room temperature and for the organic-to-inorganic conversion of LSR at elevated temperatures. The catalyst was employed in the preparation of three LSRs with varying network structures, utilizing four polysiloxanes with differing degrees of functionality. The pyrolytic behavior and organic-to-organic conversion rate of these LSRs were investigated using a thermogravimetric analyzer (TG) coupled with a Fourier transform infrared spectrometer (FTIR). The findings indicated that LSRs with the highest crosslink density exhibited the highest organic-to-inorganic conversion rate; however, they demonstrated the lowest fire-resistance. The anomalous behavior has been subjected to further analysis with respect to the mechanical properties of the LSRs and the characteristics of their network structure. LSR coatings with enhanced hardness and fire-resistance are then produced by combining the advantageous properties of both LSRs in a layer-by-layer (LBL) assembly.

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N-heterocyclic carbenes-Pt 催化体系和交联网络对液体硅橡胶热解行为的影响

液态硅橡胶（LSR）具有极佳的热稳定性，被广泛应用于需要热稳定性、耐化学性和阻燃性的领域。增强 LSR 的有机-无机转化以改善其阻燃性能是一个重要的研究领域。铂催化剂的热稳定性和 LSR 的交联网络结构对 LSR 的有机-无机转化行为有相当大的影响。本研究证明了 N-杂环碳烯（NHC）配体修饰的卡氏催化剂作为催化剂在室温下通过加氢硅烷化固化 LSR 以及在高温下将 LSR 进行有机-无机转化的功效。该催化剂用于制备具有不同网络结构的三种 LSR，使用了四种具有不同官能度的聚硅氧烷。使用热重分析仪（TG）和傅立叶变换红外光谱仪（FTIR）对这些 LSR 的热解行为和有机物到无机物的转化率进行了研究。研究结果表明，交联密度最高的 LSRs 具有最高的有机-无机转化率，但耐火性却最低。对这种反常行为的进一步分析涉及 LSR 的机械性能及其网络结构特征。然后，通过逐层（LBL）组装将两种 LSR 的优势特性结合在一起，生产出具有更高硬度和耐火性的 LSR 涂层。

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来源期刊

Polymer Degradation and Stability 化学-高分子科学

CiteScore

10.10

自引率

10.20%

发文量

325

审稿时长

23 days

期刊介绍： Polymer Degradation and Stability deals with the degradation reactions and their control which are a major preoccupation of practitioners of the many and diverse aspects of modern polymer technology. Deteriorative reactions occur during processing, when polymers are subjected to heat, oxygen and mechanical stress, and during the useful life of the materials when oxygen and sunlight are the most important degradative agencies. In more specialised applications, degradation may be induced by high energy radiation, ozone, atmospheric pollutants, mechanical stress, biological action, hydrolysis and many other influences. The mechanisms of these reactions and stabilisation processes must be understood if the technology and application of polymers are to continue to advance. The reporting of investigations of this kind is therefore a major function of this journal. However there are also new developments in polymer technology in which degradation processes find positive applications. For example, photodegradable plastics are now available, the recycling of polymeric products will become increasingly important, degradation and combustion studies are involved in the definition of the fire hazards which are associated with polymeric materials and the microelectronics industry is vitally dependent upon polymer degradation in the manufacture of its circuitry. Polymer properties may also be improved by processes like curing and grafting, the chemistry of which can be closely related to that which causes physical deterioration in other circumstances.