Search results
Results from the WOW.Com Content Network
Polyetherimide (PEI; branded as Ultem [1]) is an amorphous, amber-to-transparent thermoplastic with characteristics similar to the related plastic PEEK. When comparing PEI to PEEK, the former is cheaper but has lower impact strength and a tighter temperature range.
Polyethylenimine (PEI) or polyaziridine is a polymer with repeating units composed of the amine group and two carbon aliphatic CH 2 CH 2 spacers. Linear polyethyleneimines contain all secondary amines, in contrast to branched PEIs which contain primary, secondary and tertiary amino groups.
The thermal blanketing of 18 layers of Dacron mesh cloth sandwiched between aluminized Mylar and Kapton film also helped to protect the craft from micrometeorites. [ 14 ] The James Webb Space Telescope sunshield is made of five Kapton E sheets coated with aluminum and doped silicon to reflect heat away from the spacecraft body.
Plastic bottles made from PET are widely used for soft drinks, both still and sparkling. For beverages that are degraded by oxygen, such as beer, a multilayer structure is used. PET sandwiches an additional polyvinyl alcohol (PVOH) or polyamide (PA) layer to further reduce its oxygen permeability.
Polyamide-imides display a combination of properties from both polyamides and polyimides, such as high strength, melt processibility, [clarification needed] exceptional high heat capability, and broad chemical resistance.
Metallised films have a reflective silvery surface similar to aluminium foil and are highly flammable. The coating also reduces the permeability of the film to light, water and oxygen. The properties of the film remain, such as higher toughness, the ability to be heat sealed, and a lower density at a lower cost than an aluminium foil.
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Elastic properties describe the reversible deformation (elastic response) of a material to an applied stress. They are a subset of the material properties that provide a quantitative description of the characteristics of a material, like its strength. Material properties are most often characterized by a set of numerical parameters called moduli.