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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 ...
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 ...
PMDA is used in PET bottle recycling as a chain extender. It increases the molecular weight of the polymer by linking-together alcohol and carboxylic acid groups formed by hydrolysis of the PET. This improves the rheological properties and overall quality of the recycled plastic. [5]
Polyurethane dispersion, or PUD, is understood to be a polyurethane polymer resin dispersed in water, rather than a solvent, although some cosolvent may be used.Its manufacture involves the synthesis of polyurethanes having carboxylic acid functionality or nonionic hydrophiles like PEG (polyethylene glycol) incorporated into, or pendant from, the polymer backbone. [1]
In polymer chemistry, chain transfer is a polymerization reaction by which the activity of a growing polymer chain is transferred to another molecule: [1] [2] P ∙ + XR PX + R ∙ {\displaystyle {\ce {P}}^{\bullet }+{\ce {XR -> PX + R}}^{\bullet }} where • is the active center , P is the initial polymer chain, X is the end group , and R is ...
During the past eight years, schools in 41 states have spent millions of dollars on Yondr products — magnetically sealed fabric pouches that are used to lock up phones and other handheld tech ...
In chemistry, chain propagation (sometimes just referred to as propagation) is a process in which a reactive intermediate is continuously regenerated during the course of a chemical chain reaction. For example, in the chlorination of methane , there is a two-step propagation cycle involving as chain carriers a chlorine atom and a methyl radical ...
The Kodak Step Slim Mobile Photo Printer, for instance, lets teens take photos from their cell phones and print them out to share with friends. And the Rukus FX music mixer allows for music and ...