权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Bonding mechanism during welding of radiation cross-linked thermoplastic polymers

辐射交联热塑性聚合物焊接过程中的粘合机制

基本信息

批准号：
248297578
负责人：
Professor Dr.-Ing. Dietmar Drummer
金额：
--
依托单位：
Lehrstuhl für Kunststofftechnik (LKT)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2013
资助国家：
德国
起止时间：
2012-12-31 至 2015-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/248297578?language=en
关键词：
Bonding mechanism during welding radiation

项目摘要

If plastic components cannot be manufactured in a single fabrication step because of their com-plexity or if this should not be an objective (for example) for economic reasons, it becomes neces-sary to utilize joining technologies. Welding yields the advantages of a material-locking and media-tight joint which permits a high load transmission without using any welding filler materials. The heat needed for the complete melting of the plastic can be input into the joining zone in different ways. For example, this is carried out using convection, radiation, heat conduction or friction. Vibration welding constitutes one process which makes use of the principle of heating by means of external friction.The entanglement of molecules at the interface by interdiffusion is recognized as the main cause for the high strength of weld joints. The forces transmitted by secondary valence bonds are too low to explain the bonding mechanisms in weld joints. The formation of new valence bonds across the interface is unknown for the welding of plastics. Accordingly, since as a bonding mechanism during welding of plastics merely an interdiffusion comes into question, most weld joints are made of plas-tics from the same type. In terms of a smart material mix in products joints made of different com-ponents, with locally to the specific requirements adapted plastics, are also of particular interest. Such joints, e.g. made of high-performance engineering thermoplastics and low cost polyolefins, are currently not or only limited fabricable in the vibration welding process.For plastics in different applications, increasingly higher requirements are placed on their properties, which often cannot be implemented directly in the production or by fillers and additives. One potential possibility of influencing the properties of thermoplastics in a targeted way is provided by the cross linking of the materials with high energy irradiation. In own studies on vibration welding of radiation cross linkable thermoplastics it could be shown, that the temperature influence of the welding process can possibly lead to a thermally induced cross linking across the interface in the weld area. Thus an additional bonding mechanism would be available during welding of plastics.The aim of the project is to work out fundamental knowledge about material and process related influences on the bonding mechanisms in welding of radiation cross linked thermoplastics. The focus is on the thermally induced cross linking in the weld area during the joining process. Based on the understanding of the fundamental mechanisms of thermally induced cross linking, joining strategies are to be derived in order to promote cross linking as an additional bonding mechanism in a targeted way. This gives the possibility to produce mixed material joints, which are currently not or only limited fabricable in a common welding process.

如果塑料部件由于其复杂性而不能在单个制造步骤中制造，或者出于经济原因（例如）这不应该是一个目标，则有必要利用连接技术。焊接产生了材料锁定和介质紧密连接的优点，允许高负载传输而不使用任何焊接填充材料。塑料完全熔化所需的热量可以以不同的方式输入到连接区。例如，这是通过对流、辐射、热传导或摩擦来实现的。振动焊接是利用外摩擦加热原理的一种焊接工艺。分子在界面处的相互扩散纠缠被认为是导致焊缝高强度的主要原因。二级价键传递的力太低，无法解释焊接接头中的键合机制。对于塑料的焊接，在界面上形成新的价键是未知的。因此，由于塑料焊接过程中的粘合机制仅仅是相互扩散，因此大多数焊接接头都是由同一类型的塑料制成的。在智能材料组合方面，由不同组件制成的产品接头，与当地的特定要求相适应的塑料，也特别令人感兴趣。这种接头，例如由高性能工程热塑性塑料和低成本聚烯烃制成，目前不能或只能在振动焊接工艺中制造。对于不同用途的塑料，对其性能的要求越来越高，而这些要求往往不能直接在生产中实现，也不能通过填料和添加剂来实现。有针对性地影响热塑性塑料性能的一种潜在可能性是通过高能辐照使材料交联。对辐射交联热塑性塑料振动焊接的研究表明，焊接过程的温度影响可能导致焊接区域界面上的热诱导交联。因此，在塑料焊接过程中，可以获得一种额外的粘合机制。该项目的目的是研究材料和工艺对辐射交联热塑性塑料焊接中粘合机制的影响的基本知识。重点是在焊接过程中焊接区域的热诱导交联。在了解热诱导交联基本机理的基础上，推导出相应的连接策略，从而有针对性地促进交联作为一种附加的键合机制。这就提供了生产混合材料接头的可能性，这是目前在普通焊接工艺中无法或只能有限地可制造的。