Influence of microstructure, crystalline form, and crystallinity on free radical evolution and properties of radiation sterilized PP

IF 2.8 3区物理与天体物理 Q3 CHEMISTRY, PHYSICAL

Radiation Physics and Chemistry Pub Date : 2025-05-27 DOI:10.1016/j.radphyschem.2025.112984

G. Stamboliev , D. Milicevic , T. Barudzija , D. Milivojevic , E. Suljovrujic

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引用次数: 0

Abstract

Polypropylene (PP), a widely used material in the medical industry, mainly for single-use (SU) medical devices such as syringes and disposable containers, belongs to the group of polymers sensitive to ionizing radiation, even at relatively low doses (in the range of sterilization ones) and undergoes excessive oxidative degradation and deterioration in properties upon irradiation in air. Despite its simple chemical composition, commercial PP is sensitive to processing conditions due to its high isotacticity, and it can crystallize into several crystal forms depending on molecular characteristics. All of them show significant applicability in the medical industry but different structure/property sensitivity during and, in some cases, long after exposure to ionizing radiation.

Herein, rapid quenching and slow cooling procedures were applied after compression molding to obtain PP samples in mesomorphic (smectic) and monoclinic forms. After that, samples were exposed to gamma radiation, and the annealing treatment was applied to the part of the irradiated samples. The presence and evolution of free radicals were followed using electron spin resonance (ESR) spectroscopy for up to 6 months. Additional characterization was conducted by optical microscopy (OM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), wide angle X-ray diffraction (WAXD), and differential scanning calorimetry (DSC). The results are analyzed, compared, and discussed, emphasizing the maximal dose of 50 kGy for sterilizing medical devices. Our findings show that, depending on the initial preparation conditions, the radiation-induced changes in structure and properties and the evolution of free radicals differ significantly. The applied annealing procedure substantially reduces the concentration of long-lived free radicals and can benefit the long-term stabilization of the irradiated PP.

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微观结构、晶型和结晶度对辐射灭菌PP自由基演化和性能的影响

聚丙烯（PP）是医疗工业中广泛使用的材料，主要用于注射器和一次性容器等一次性医疗器械，它属于对电离辐射敏感的聚合物，即使在相对较低的剂量下（在灭菌剂量范围内），在空气中照射时也会发生过度的氧化降解和性能恶化。尽管其化学成分简单，但由于其高等规性，商用PP对加工条件很敏感，并且可以根据分子特性结晶成几种晶体形式。所有这些材料都在医疗工业中显示出显著的适用性，但在暴露于电离辐射期间和某些情况下暴露于电离辐射后很长时间内，结构/性能敏感性不同。在这里，压缩成型后采用快速淬火和缓慢冷却程序来获得中晶（近晶）和单斜晶形式的PP样品。之后，将样品暴露在伽马辐射下，对辐照后的部分样品进行退火处理。使用电子自旋共振（ESR）光谱跟踪自由基的存在和演化长达6个月。通过光学显微镜（OM）、扫描电镜（SEM）、傅里叶变换红外光谱（FTIR）、广角x射线衍射（WAXD）和差示扫描量热法（DSC）进行了进一步的表征。对结果进行了分析、比较和讨论，强调医疗器械灭菌的最大剂量为50 kGy。我们的研究结果表明，根据初始制备条件的不同，辐射引起的结构和性质的变化以及自由基的演变有显著差异。所应用的退火程序大大降低了长寿命自由基的浓度，有利于辐照PP的长期稳定。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Radiation Physics and Chemistry 化学-核科学技术

CiteScore

5.60

自引率

17.20%

发文量

574

审稿时长

12 weeks

期刊介绍： Radiation Physics and Chemistry is a multidisciplinary journal that provides a medium for publication of substantial and original papers, reviews, and short communications which focus on research and developments involving ionizing radiation in radiation physics, radiation chemistry and radiation processing. The journal aims to publish papers with significance to an international audience, containing substantial novelty and scientific impact. The Editors reserve the rights to reject, with or without external review, papers that do not meet these criteria. This could include papers that are very similar to previous publications, only with changed target substrates, employed materials, analyzed sites and experimental methods, report results without presenting new insights and/or hypothesis testing, or do not focus on the radiation effects.