Enhancing flame retardancy and mechanical performance of polycarbonate with cinnamate-containing liquid crystalline copolyester

IF 7.4 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability Pub Date : 2025-09-18 DOI:10.1016/j.polymdegradstab.2025.111675

Yao Yan, Zuanxin Yang, Songming Chen, Rong Yang

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引用次数: 0

Abstract

The flame-retardant modification of polymers, while preserving or enhancing their mechanical properties, is critical for engineering plastics. In this study, we develop flame-retardant polycarbonate (PC) composites with improved mechanical performance by incorporating cinnamate-containing liquid crystalline copolyester (CLCP). During the injection molding process, CLCP forms oriented microfibrils in situ, boosting the tensile strength of the composites by up to 66 %. The cinnamate groups in CLCP undergo radical-initiated thermal crosslinking, which increases melt viscosity, prevents dripping, and achieves a UL-94 V-0 rating. The primary flame retardancy mechanism occurs in the condensed phase: early decomposition of CLCP triggers thermal crosslinking, leading to the formation of a dense, graphitized char layer that reduces the peak heat release rate (PHRR) by 46.8 %, total smoke production by 17.9 %, and increases the limiting oxygen index (LOI) to 32.5 % (compared to 27.0 % for neat PC). This dual-functionality of CLCP addresses both the flammability and mechanical limitations of PC, making it a promising candidate for engineering applications requiring high-performance materials. This work introduces a novel molecular design strategy, integrating liquid crystallinity and cinnamate crosslinking, to enhance both flame resistance and mechanical properties in engineering plastics.

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用含肉桂酸酯液晶共聚酯增强聚碳酸酯的阻燃性和力学性能

对聚合物进行阻燃改性，在保持或增强其机械性能的同时，对工程塑料至关重要。在本研究中，我们通过添加含肉桂酸的液晶共聚酯（CLCP），开发了具有改善机械性能的阻燃聚碳酸酯（PC）复合材料。在注射成型过程中，CLCP在原位形成定向微纤维，将复合材料的抗拉强度提高了66%。CLCP中的肉桂酸基团经过自由基引发的热交联，从而增加熔体粘度，防止滴落，并达到UL-94 V-0等级。主要的阻燃机制发生在凝聚相：CLCP的早期分解引发热交联，导致形成致密的石墨化炭层，使峰值放热率（PHRR）降低46.8%，总烟产量降低17.9%，并将极限氧指数（LOI）提高到32.5%（纯PC为27.0%）。CLCP的这种双重功能解决了PC的易燃性和机械限制，使其成为需要高性能材料的工程应用的有希望的候选者。本工作介绍了一种新的分子设计策略，结合液体结晶性和肉桂酸交联，以提高工程塑料的阻燃性和机械性能。

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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.