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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 ...
Water content Chemical composition I non-ionic low water content: galyfilcon A 60 47% – lotrafilcon A 140 24% DMA, siloxane, TRIS: lotrafilcon B 110 33% polymacon: 7.5 36% HEMA: tetrafilcon 9.0 43.5% HEMA, MMA, NVP: II non-ionic high water content: alphafilcon A 22.9 66% HEMA, NVP: hilafilcon A 26.9 70% omafilcon A 19.6 62% HEMA, PC: III ...
Flexible PVC is also used in inflatable products, such as water beds and pool toys. PVC is also a common material in vinyl action figures, especially in countries such as Japan, where the material is used extensively in so-called Sofubi figures (Soft vinyl toys [7]). As PVC bends easily and has a tendency to be bent during transit, a method to ...
TPV can be used to make durable seals, gaskets, and grommets that are resistant to flex fatigue, harsh temperatures, and chemicals, as well as for a variety of sealing applications, including pipe seals, bridge expansion joints and curtain walls, parts for potable water, and pipe seals for sewer and drainage.
Made with a soft-touch TPU rubber that's lightweight and tough as nails, the band is made to handle all-day wear and tear—all while staying comfortable on the wrist. ... You'd be hard-pressed to ...
$54.99 at amazon.com. Choose the Right Covers. Outdoor furniture comes in all shapes and sizes, so finding a cover that fits well and doesn’t leave large gaps for water or snow to seep in can be ...
These crystallites form covalent netpoints which prevent the polymer from reforming its usual coiled structure. The hard to soft segment ratio is often between 5/95 and 95/5, but ideally this ratio is between 20/80 and 80/20. [12] The shape-memory polymers are effectively viscoelastic and many models and analysis methods exist.
A material is also considered hard if it resists plastic deformation. If a material has short covalent bonds, atomic dislocations that lead to plastic deformation are less likely to occur than in materials with longer, delocalized bonds. If a material contains many delocalized bonds it is likely to be soft. [10]