Rubber Compounding Ingredients Need Theory And Innovation

The objectives of rubber compounding may be essentially defined as providing optimised performance and processability, generally at minimum cost, by the incorporation of non-rubber ingredients. Optimised performance in this context refers not only to mechanical properties but also, for example, resistance to bacteria or particular chemicals. In some applications a rubber may also need to be coloured, or bonded to another material, and further ingredients may be required. For many years, rubber compounding was largely empirical and frequently described as a black art. Today it is practised predominantly on the basis of scientific principles elucidated over years of study and is still the subject of intensive research. In this new report Claude Hepburn reviews the following range of compounding ingredients, considering the range of materials available, their particular actions and recent interesting advances: Process and extender oils; Process aids and surfactants; Coupling agents and adhesion promoters; Fire retardants, bactericides and blowing agents, colourants and odourants. An additional indexed section containing several hundred abstracts from the Polymer Library provides many more examples of novel materials and their applications.

This report covers vulcanising systems antidegradants and particulate fillers. Professor Claude Hepburn describes the reasons why these materials are used, the ways in which they work, and recent interesting advances. In addition, an indexed section containing over 300 abstracts from international literature provides many more examples of novel materials and their actions.

Recent changes in Screw extruders for rubber have been driven by demands for accuracy and economy, increased understanding of the underlying principles, and improvements in related technologies such as control systems and computing power. An additional indexed section containing several hundred abstracts from the Rapra Polymer Library database provides useful references for further reading.

This report describes the geometric structure of modular extruders, development of the various units of an extruder and their functions, the flow mechanisms and models of their behaviour and experimental studies of extruder performance and applications. An additional indexed section containing several hundred abstracts from the Rapra Polymer Library database gives useful references for further reading.

Rubber components are used in many demanding applications, from tyres and seals to gloves and medical devices, and failure can be catastrophic. This review of Rubber Product Failure outlines and illustrates the common causes of failure, while addressing ways of avoiding it. There has been increasing pressure to improve performance so that rubbers can be used at higher temperatures and in harsher environments. For example, the under-the-bonnet temperature has increased in some vehicles and new medical devices require longer lifetimes in potentially degrading biological fluids. The expectations of tyre performance in particular are increasing, and retreads have been in the spotlight for failures. The definition of failure depends on the application. For example, a racing car engine seal that lasts for one race may be acceptable, but in a normal car a life span of 10 years is more reasonable. If appearance is critical as in surface coatings and paints, then discolouration is failure, whilst in seals leakage is not acceptable. Each rubber product must be fit for the use specified by the consumer. Failure analysis is critical to product improvement. the cause of the problem can be much harder to find. It can range from a design fault to poor material selection, to processing problems, to manufacturing errors such as poor dimensional tolerances, to poor installation, product abuse and unexpected service conditions. The rubber technologist must become a detective, gathering evidence, understanding the material type and using deductive reasoning. Testing and analysis of failed materials and components add to the information available for failure analysis. For example, stored aged tyres appeared superficially to be alright for use, but on drum testing small cracks grew more quickly than in new tyres leading to rapid failure in service. Quality control procedures such as product inspection, testing and material quality checks can help to reach 100 percent reliability. In critical applications such as electricians' gloves for high voltage working, gloves are inspected before each use, while engine seals may be routinely replaced before the expected lifetime to avoid problems. in the literature is not high. However, several reviews have been written on specific products and references can be found at the end of this review. Around 400 abstracts from papers in the Polymer Library are included with an index. Subjects covered include tyre wear and failure, seals, engine components, rubber bonding failure, rubber failure due to chloramine in water, tank treads, gloves and condoms, medical devices and EPDM roofing membranes.

This is an overview of the factors tyre compounders and engineers must consider when developing compounds for tyres. It discusses compounding ingredients for tyre rubbers by class including polymer types. The future of tyres in vehicles is also outlined. An additional indexed section containing several hundred abstracts from the Polymer Library provides useful references for further reading.

This report provides an excellent, clearly written report on the state-of-the-art of food contact elastomers. In the UK, the Ministry of Agriculture Fisheries and Food (MAFF), industry and Rapra have combined forces to study the issues surrounding rubbers in contact with food. A survey has been carried out of the food processing industry to determine which rubber products come into contact with food, contact area, duration of contact and temperature of contact. The results of this survey are found in the report and a compilation of data tables on each food industry studied is included as an appendix. An additional indexed section containing several hundred abstracts from the Rapra Polymer Library database gives useful references for further reading.

Glassy and ductile plastics require toughening to improve their range of usefulness, particularly for engineering applications. Rubber-modified, toughened thermoplastics are already in widespread use. This review sets out to introduce this field and describe the state-of-the-art. An additional indexed section containing several hundred abstracts from the Rapra Polymer Library database gives useful references for further reading.