-

Results 1 - 10 of 2265 for  Wikipedia / Polymers / Wikipedia    (3565152 articles)

Coordination polymers print that page

Coordination_figure

Coordination polymers can be classified in a number of different ways due to particular aspects of structure and composition. One important classification is referred to as dimensionality . A structure can be determined to be one, two or three dimensional, depending on the number of directions

Ferroelectric polymers print that page

Ferroelectric polymers , such as polyvinylidene fluoride (PVDF), are used in acoustic transducers and electromechanical actuators because of their inherent piezoelectric response, and as heat sensors because of their inherent pyroelectric response. [ 3 ] Figure 1: Structure of Poly(vinylidene

wikipedia.org | 2011/5/19 17:17:15

Chemically Assisted Degradation of Polymers print that page

cases is unsaturated (contains double bonds), however a reaction will still occur in saturated polymers (those containing only single bonds). When reaction occurs, scission of the polymer chain (breaking of double covalent bonds) takes place forming decomposition products: Chain scission

wikipedia.org | 2010/9/26 9:08:26

Spinning (polymers) print that page

edit ] Wet spinning Wet spinning is the oldest of the four processes. This process is used for polymers that need to be dissolved in a solvent to be spun. The spinneret is submerged in a chemical bath that causes the fiber to precipitate , and then solidify, as it emerges. The process gets

wikipedia.org | 2011/4/26 20:01:29

Chemically assisted degradation of polymers print that page

cases is unsaturated (contains double bonds), however a reaction will still occur in saturated polymers (those containing only single bonds). When reaction occurs, scission of the polymer chain (breaking of double covalent bonds) takes place forming decomposition products: Chain scission

wikipedia.org | 2011/4/23 9:52:27

Electroactive polymers print that page

The mixture would then solidify into a polymeric material that exhibited a piezoelectric effect. Polymers that respond to environmental conditions other than an applied electrical current have also been a large part of this area of study. In 1949, Katchalsky et. al. demonstrated that when

wikipedia.org | 2011/5/23 14:17:42

Antimicrobial polymers print that page

food preventing bacterial reproduction, also known as bacterial conjugation . [ 2 ] Antimicrobial polymers commonly kill bacteria through this first method, which is accomplished through a series of steps, shown in Figure 1. [ 1 ] First, the polymer must adsorb onto the bacterial cell wall

wikipedia.org | 2010/9/24 19:50:47

Fire-safe polymers print that page

Louis Gay-Lussac in 1821. [ 4 ] [ edit ] Developments Since WWII Research on fire-retardant polymers was bolstered by the need for new types of synthetic polymers in World War II . The combination of a halogenated paraffin and antimony oxide was found to be successful as a fire retardant

wikipedia.org | 2010/9/25 1:24:54

Supramolecular polymers print that page

Quadruple_Hydrogen_Bond_AngewChemIntEd_1998_v37_p75

repeat units are held together by noncovalent bonds . Non-covalent forces that hold supramolecular polymers together include coordination, π-π interactions, and hydrogen bonding. One system that has been demonstrated uses quadruple hydrogen bonds to form supramolecular polymers . Functionalization

Crystallization of polymers print that page

Spherulite1

Polymers are composed of long molecular chains which form irregular, entangled coils in the melt. Some polymers retain such a disordered structure upon freezing and thus convert into amorphous solids. In other polymers , the chains rearrange upon freezing and form partly ordered regions with