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At or near the final stages of production, the material is treated with a chain extender. Typically, chain extenders are bifunctional, i.e., they have two functional groups, which can link together two polymers. Representative classes of chain extenders are diglycidyl ethers, diols, diamines, or dianhydrides. Chain extenders are often applied ...
1,6-Hexanediol can improve the hardness and flexibility of polyesters as it contains a fairly long hydrocarbon chain. In polyurethanes, it is used as a chain extender , and the resulting modified polyurethane has high resistance to hydrolysis as well as mechanical strength, but with a low glass transition temperature.
TPU is a block copolymer consisting of alternating sequences of hard and soft segments or domains formed by the reaction of (1) diisocyanates with short-chain diols (so-called chain extenders) and (2) diisocyanates with long-chain diols. By varying the ratio, structure and/or molecular weight of the reaction compounds, an enormous variety of ...
2-Methylpentamethylenediamine can also be used as a chain extender for polyurethane applications, and in particular with PUDs. [3] [4] Its derivatives like aspartic esters, secondary amines, aldimines and ketoimines serve as curatives in polyurea systems. In polyamides, 2-Methylpentamethylenediamine acts as a crystallinity disruptor.
BMW and Yamaha Motor have invested in U.S.-based rare earths processing startup Phoenix Tailings, the latest move by manufacturers to boost production of the strategic metals outside of China.
The most important chain extenders are ethylene glycol, 1,4-butanediol (1,4-BDO or BDO), 1,6-hexanediol, cyclohexane dimethanol and hydroquinone bis(2-hydroxyethyl) ether (HQEE). All of these glycols form polyurethanes that phase separate well and form well defined hard segment domains, and are melt processable.
Teens and tweens are notoriously hard to please, which can make gift-giving a little tricky. Luckily, we've rounded up all the season's hottest gifts for the 10+ set with some help from ...
It is a diamine and thus in polymer science terms is a Chain extender rather than a chain terminator. Chain extenders ( f = 2) and cross linkers ( f ≥ 3) are low molecular weight amine terminated compounds that play an important role in polyurea compounds, elastomers and adhesives .