Sulfur vulcanization sulfur is not miscible in the polymer prior to vulcanization and attention is paid to prevent sulfur bloom, where it migrates to the surface of the article. Accelerators act much like catalysts allowing vulcanisation to be performed cooler yet faster and with a more efficient use of sulfur. They achieve this by reacting with and breaking the sulfur ring to form a reactive intermediate, referred to as a sulfurating agent. This in turn reacts with cure sites in the rubber to bring about vulcanization. There are two major classes of vulcanization accelerators: primary accelerators and secondary accelerators (also known as
Polymer blend more than one kind of polymer. A new polymers modification process, based on a simple mechanical mixture of two polymers first appeared when Thomas Hancock got one mixture of natural rubber with gutta-percha. This process generated a new polymer class called "polymer blends". Polymer blends can be broadly divided into three categories: The use of the term polymer alloy for a polymer blend is discouraged, as the former term includes multiphase copolymers but excludes incompatible polymer blends. Examples of miscible polymer blends: Polymer blends can be used as thermoplastic elastomer Polymer blend A polymer blend, or polymer mixture, is a