The new heat aging test box GBT7141-2008 standard foreword

**Foreword - New Heat Aging Test Chamber Standard GBT 7141-2008** This standard has been revised based on the ASTM D5510:1994 (2001) standard, which outlines the thermal aging of oxidatively degradable plastics. The revision was carried out in accordance with the original ASTM specification, while taking into account China's specific conditions and industry requirements. To better suit national needs, several technical adjustments were made to the original ASTM D5510:1994 (2001). These differences are clearly marked in the text with vertical single lines next to the relevant terms. A detailed list of these modifications and their underlying reasons is provided in Appendix A for reference. In addition to the technical changes, several editorial adjustments have been made to improve clarity and usability: - The term "ASTM standard" has been replaced with "this standard." - The original description of ASTM D5510:1994 (2001) has been removed. - All notes and references from the original ASTM document have been deleted. - An introduction to the preface of national standards has been added. - Where applicable, ASTM standards in the normative references have been replaced with corresponding Chinese or international standards. - Appendix A has been included to provide additional guidance. This standard supersedes GB/T 7141-1992, which focused solely on the hot air aging test method using a forced air ventilation chamber. In contrast, the new standard introduces two types of heat aging test chambers: one using natural convection and the other using forced ventilation. Each is suitable for different sample thicknesses, offering more flexibility and accuracy in testing. Furthermore, this standard provides more comprehensive guidelines for selecting test cycles and offers multiple testing approaches. It not only includes methods for evaluating materials at a single temperature but also covers tests conducted across a range of temperatures. This allows for a more thorough assessment of material performance, including its temperature stability and expected service life under various conditions. Appendix A serves as an informative annex, providing supplementary information to support the main content of the standard. The standard was proposed by the China Petroleum and Chemical Industry Association and is managed by the National Plastics Standardization Technical Committee. It was developed by Guangzhou Synthetic Materials Research Institute Co., Ltd. and Beijing Tianjia Technology Co., Ltd. Key contributors include Wang Haojiang, Shao Fang, Li Jie, Shan Jinhua, Yang Xinhua, Yang Yunong, and Xie Zhenping. This standard replaces previous versions, including GB/T 7141-1986 and GB/T 7141-1992.

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