Vulcanization system vulcanizing agents

Curing Systems. The most commonly used vulcanizing agent for the polyethers not containing AGE, that is, ECH and ECH—EO, is 2-mercaptoimidazoline, also called ethylenethiourea [96-45-7]. Other commercially appHed curing agents include derivatives of 2,5-dimercapto-l,3,4-thiadiazole, trithiocyanuric acid and derivatives, bisphenols, diamines, and other substituted thioureas. 

Ha [29] has shown that in PP-HDPE (of high-den-sity PE) dynamically cured EPDM, the cured EPDM act as a compatibilizer to the HDPE-PP system. Blending was done in two ways. EPDM was cured first and then blended with PP and HDPE. In the second case, EPDM was cured in the presence of PP and HDPE using dicu-myl peroxide (DCP) as the vulcanizing agent. In EPDM-rich composition, mechanical properties were increased by increasing the concentration of DCP, whereas in PP-rich composition, the reverse was the case. 

The basic compounding formulation specifies the minimum requirement of fillers, vulcanizing agents, and other substances that must be added to the rubber compound to achieve the desired properties. After the rubber, cure system and reinforcing filers have been selected it will be necessary to make several adjustments before all requirements are satisfied. It is generally sensible to start with the simplest mix formula for meeting the requirements. The recipe or the formula is usually written on the basis of hundred parts of rubber. For example if 5 parts of zinc oxide is to be added it is denoted as 5 phr (five parts per hundred rubber). Elementary compounding... 

Interactions with Closure Systems. Elastomeric and plastic container and closure systems release leachable compounds into the liquid dosage form, such as nitrosamines, monomers, plasticizers, accelerators, antioxidants, and vulcanizing agents [44], Each type of container and closure with different composition and/or design proposed for marketing the drug or physician s samples has to be tested and stability data should be developed. Containers should be stored upright, on their side, and inverted in order to determine if container-closure interactions affect product stability [6,45]. 

A sulfur-curing system thus has basically four components a sulfur vulcanizing agent, an accelerator (sometimes combinations of accelerators), a metal oxide, and a fatty acid. In addition, in order to improve... 

Vulcanization, named after Vulcan, the Roman God of Fire, describes the process by which physically soft, compounded rubber materials are converted into high-quality engineering products. The vulcanization system constitutes the fourth component in an elastomeric formulation and functions by inserting crosslinks between adjacent polymer chains in the compoimd. A typical vulcanization system in a compound consists of three components (1) activators (2) vulcanizing agents, typically sulfur and (3) accelerators. 

Rubbor Vulcanization Chomicals. The vulcanization systems consist of the following components the vulcanizing agent such as sulfur, the accelerator to activate the sulfur, a retarder to help control the rate of vulcanization, and an activator such as zinc oxide and stearic acid. 

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