A New Class of Oxyimides: Oxyimide Ethers and their Use as Flame Retardants

Oxyimides have gained wide interest in different applications because of radical generating properties, such as flame retardants in various polymers. As polyamide-6 (PA6) is highly flammable and shows burning dripping during incineration the mentioned issues have to be overcome by the use of a flame retardant. All previously developed oxyimides already show these properties, but this is based on the ester structure with the consequence of transesterification/transamidation in polyesters/polyamides. In this work, a new class of oxyimides based on ether bonds is synthesized. Oxyimide ethers do not degrade PA6, only sometimes slightly increase MVR, and show excellent flame retardancy in PA6. Depending on the structure, UL 94 V-0 can be reached with very low loadings. This makes oxyimide ethers an alternative to commonly used flame retardants for PA6.     

408ULS双检系统典型故障的排除

408ULS双检系统作为目前海上地震勘探的主流仪器,用于采集地震数据,但在实际生产中,遇到了很多制约施工的问题。本文介绍了408ULS双检系统在施工中出现的三个典型故障,即408ULS仪器对双检的识别错误、408ULS与双检的匹配、408ULS数传错误等问题,并提出了相应的解决方法。     

浅谈LT408／428的软件安装及应用

本文对408UL/428XL仪器的野外重要辅助设备LT408/428的软件安装方法进行了分析,并从该软件的备份和重装及设备测试等方面对其进行了全面地介绍,同时根据大量的野外实践经验,总结出一些软件应用过程中的常见问题及注意事项.     

美国UL 674新老标准的主要技术差异及新增内容介绍

对UL 674标准第四版与第三版的主要技术差异进行了分析对比,并对新标准中增加的内容进行了简单的介绍.     

Modelling the vertical UL 94 test: competition and collaboration between melt dripping,gasification and combustion

An experimental and numerical investigation of the effect of bisphenol A bis(diphenyl phosphate) (BDP) and polytetrafluoroethylene (PTFE) on the fire behaviour of bisphenol A polycarbonate/acrylonitrile butadiene styrene (PC/ABS) in the vertical UL 94 scenario is presented. Four PC/ABS blends were discussed, which satisfy different UL 94 classifications due to the competing effects of gasification, charring, flame inhibition and melt flow/dripping. For numerical investigation, the particle finite element method (PFEM) is used. Its capability to model the complex fire behaviour of polymers in the UL 94 is analysed. The materials' properties are characterised, in particular the additives impact on the dripping behaviour during thermal exposure. BDP is an efficient plasticiser; adding PTFE prevents dripping by causing a flow limit. PFEM simulations reproduce the dripping and burning behaviour, in particular the competition between gasification and dripping. The thermal impact of both the burner and the flame is approximated taking into account flame inhibition, charring and effective heat of combustion. PFEM is a promising numerical tool for the investigation of the fire behaviour of polymers, particularly when large deformations are involved. Not only the principal phenomena but also the different UL 94 classifications and the extinction times are well predicted. Copyright © 2014 John Wiley & Sons, Ltd.     

150℃无卤低烟阻燃无铅可硫化型乙丙橡胶配方

介绍了150℃无卤低烟阻燃无铅可硫化型乙丙橡胶配方的研制过程,使用无铅类稳定剂、无卤类增塑剂、金属氢氧化物阻燃剂等辅助材料,确保成品电线符合AWM UL 758/2017标准要求.     

408UL采集链的装配方法

本文介绍了408UL采集链的三种装配方法——利用TMS408系统、LT428和PC机来装配,并特别着重地介绍了在没有TMS408和LT428的情况下通过普通电脑的超级终端功能来实现采集链装配的方法。希望这些经验能给有需要的同行们提供一点帮助。     

SN388、408UL仪器系统和同步系统联机启动稳定性分析

随着物探技术的发展，有时需要不同型号的遥测地震采集系统联机来同步采集地震数据，但两台仪器联机生产时常出现触发采集不稳定的现象。本文介绍了仪器与同步系统的启动过程，并通过实例对联机启动不稳定的现象进行了分析，找出了联机启动不稳定的原因，并介绍了故障排除方法。     

408UL地震仪排列绕道参数快速设置方法研究

法国SERCEL公司生产的408UL数字遥测地震仪,采集道数多、排列布设灵活、生产效率高。但是,在山地、水网等复杂地表施工时,系统绕道设置费时且极易出错。针对这一问题,尝试利用OFFICE的EXCEL电子表格软件直接生成绕道设置文件,不但能大大提高绕道设置效率,缩短排列生成时间,而且还能为进一步发挥408UL地震仪仪器的优势提供技术上的支持。     

PEEK polymer flammability and the inadequacy of the UL‐94 classification

Fire safety is dependent on reliable information on material properties, particularly relating to burning behaviour. The Underwriters Laboratory UL‐94 test is a widely used simple Bunsen burner test for vertically upward flame spread. Aryl polyetheretherketones (PEEK) are polymers of exceptional thermal stability, typically decomposing at around 600°C and forming 50% carbonaceous char residue. Tests on seven PEEK polymers, and two related materials, in independent laboratories have revealed large inconsistencies in both the final broad classification and the scatter within each set of test results. In many cases, this variance is so large that if samples from the same batch of many of the materials were repeatedly submitted to test laboratories, this would ultimately result in one set remaining below the maximum burn time criteria, and so meeting the least flammable V‐0 rating. Initial data are presented indicating that a larger ignition source actually results in shorter burning times and more consistent burning behaviour. The reported behaviour of PEEK indicates that the inconsistencies reported here are not a function of inconsistencies in the material itself but rather a consequence of the low applied heat flux of the test method being very close to the critical heat flux for ignition of the PEEK polymer, which is rather high. With higher applied heat fluxes, this generates sufficient heat for a protective char to form, creating an effective barrier to further flame spread. Copyright © 2011 John Wiley & Sons, Ltd.