1.1 本规程涵盖了两个程序A和B，用于测定细菌对模制和预制制品、管材、棒材、板材和薄膜材料形式的塑料财产的影响。与程序a相比，程序B在受试细菌和试样之间提供了更广泛的接触。光学、机械和电气财产的变化可通过适用的ASTM方法确定。 1.2 以国际单位制表示的数值应视为标准。 1.3 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践，并确定监管限制的适用性。 1.4 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《国际标准、指南和建议制定原则决定》中确立的国际公认标准化原则制定的。 =====意义和用途====== 4.1 塑料材料的树脂部分通常抗细菌，因为它不作为细菌生长的碳源。通常是其他成分，如增塑剂、润滑剂、稳定剂和着色剂，对塑料材料造成细菌攻击。当塑料在有利于微生物攻击的高温和湿度条件下使用时，建立塑料对微生物攻击的抵抗力非常重要。 4.2 预期效果如下: 4.2.1 表面侵蚀、变色和透射损失（光学）。 4.2.2 去除易受影响的增塑剂、改性剂和润滑剂，导致模量（刚度）增加，重量、尺寸和其他物理财产发生变化，电气财产恶化，例如绝缘电阻、介电常数、功率因数和介电强度。 4.3 通常，电财产的变化主要是由于表面生长和相关水分，以及细菌代谢产物引起的pH值变化。其他影响包括增塑剂、润滑剂和其他加工添加剂的不均匀分散导致的优先增长。 在薄膜形式的产品或表面与体积比高的涂层上，以及在生物体利用增塑剂和润滑剂等营养物质时，可能会观察到明显的物理变化。 4.4 由于生物的攻击涉及由于局部加速和抑制而产生的大量变化，因此再现性的顺序可能相当低。为了确保对行为的估计不太乐观，应报告观察到的最大恶化程度。 4.5 试样的处理，如暴露于浸出、风化、热处理等，可能会对塑料的抗细菌性产生重大影响。 本文件不包括这些影响的确定。

1.1 This practice covers two procedures, A and B, for determining the effect of bacteria on the properties of plastics in the form of molded and fabricated articles, tubes, rods, sheets, and film materials. Procedure B provides a more extensive contact between the test bacteria and the specimens than does Procedure A. Changes in optical, mechanical, and electrical properties may be determined by the applicable ASTM methods. 1.2 The values stated in SI units are to be regarded as the standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 4.1 The resin portion of plastic materials is usually resistant to bacteria, in that it does not serve as a carbon source for the growth of bacteria. It is generally the other components, such as plasticizers, lubricants, stabilizers, and colorants that are responsible for bacterial attack on plastic materials. It is important to establish the resistance of plastics to microbial attack when plastics are used under conditions of high temperature and humidity favorable for such attack. 4.2 The effects to be expected are: 4.2.1 Surface attack, discoloration, and loss of transmission (optical). 4.2.2 Removal of susceptible plasticizers, modifiers, and lubricants, resulting in increased modulus (stiffness), changes in weight, dimensions, and other physical properties, and deterioration of electrical properties such as insulation resistance, dielectric constant, power factor, and dielectric strength. 4.3 Often the changes in electrical properties are due principally to surface growth and associated moisture, and to pH changes caused by products of bacterial metabolism. Other effects include preferential growths caused by nonuniform dispersion of plasticizers, lubricants, and other processing additives. Pronounced physical changes may be observed on products in film form or as coatings where the ratio of surface to volume is high, and where nutrient materials such as plasticizers and lubricants continue to diffuse to the surface as they are utilized by the organisms. 4.4 Since attack by organisms involves a large element of change due to local accelerations and inhibitions, the order of reproducibility may be rather low. To assure that estimates of behavior are not too optimistic, the greatest observed degree of deterioration should be reported. 4.5 Conditioning of specimens such as exposure to leaching, weathering, heat treatment, etc., may have significant effects on the resistance of plastics to bacteria. Determination of these effects is not covered in this document.