Shape Memory Performance of Thermoplastic Polyvinylidene fluoride/Acrylic Copolymer Blends Physically Crosslinked by Tiny Crystals.
Summary of "Shape Memory Performance of Thermoplastic Polyvinylidene fluoride/Acrylic Copolymer Blends Physically Crosslinked by Tiny Crystals."
Polyvinylidene fluoride (PVDF)/acrylic copolymer (ACP) blends are a typical miscible crystalline/amorphous system over the whole composition range. Our previous investigation indicated that blend samples with controlled component ratios and crystallization conditions exhibit good shape memory properties (J. Phys. Chem. B 2012, 116, 1256-1264). In this work, we systematically investigated the cold crystallization temperature effects on the crystal morphologies and the shape memory properties for the 50/50 blend. It was found that the quenched blend is an amorphous material with a low glass transition temperature. Annealing at temperatures above Tg of the blend induces crystallization of PVDF from the miscible amorphous PVDF/ACP phase, leading to an increased glass transition temperature of the blend. High annealing temperature results in large PVDF spherulites, while low annealing temperature produces tiny crystals in the blend. Furthermore, tiny crystals serve as the physical crosslink points and the amorphous regions among them act as the reversible phase for the blend materials during the mechanical deformations. Therefore, the PVDF/ACP blends with tiny crystals show not only high shape fixity but also excellent recovery ratios.
Affiliation
Journal Details
This article was published in the following journal.
Name: ACS applied materials & interfaces
ISSN: 1944-8252
Pages:
Links
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/22897334
- DOI: http://dx.doi.org/10.1021/am301161s
Medical and Biotech [MESH] Definitions
Calcium Fluoride
Calcium fluoride. Occurring in nature as the mineral fluorite or fluorspar. It is the primary source of fluorine and its compounds. Pure calcium fluoride is used as a catalyst in dehydration and dehydrogenation and is used to fluoridate drinking water. (From Merck Index, 11th ed)
Pyran Copolymer
Copolymer of divinyl ether and maleic anhydride that acts as an immunostimulant with antineoplastic and anti-infective properties. It is used in combination with other antineoplastic agents.
Sodium Fluoride
A source of inorganic fluoride which is used topically to prevent dental caries.
Tin Fluorides
Inorganic fluorides of tin. They include both stannic fluoride (tin tetrafluoride) and stannous fluoride (tin difluoride). The latter is used in the prevention of dental caries.
Acidulated Phosphate Fluoride
A sodium fluoride solution, paste or powder, which has been acidulated to pH 3 to 4 and buffered with a phosphate. It is used in the prevention of dental caries.
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