Year: 1998
Type: other
Abstract: Investigations have been carried out to introduce plyurethanes as new ferroelectric and pyroelectric polymers and to get the origin of ferroelectric behavior in polyurethanes.To achieve this pulpose, these polymers were studied extensively both in experimental and theoretical view-points.In the molecular chanins of polyurethane, bydrogen bonds can be formed btween the adjacent N-H and C:O groups of carbamate group (-NH-COO-).The hydrogen bonds of polyurethanes are weaker than those of polyamides due to the ether groups in the ployurethane chains.It is expected that the weak hydrogen bonds enhance the rotation of depoles and influence the ferroelectric and pyroelectric behaviors.The polyurethanes discussed in this study were synthesized by thepolyaddition method.The synthesized polymers were aliphatic and aromatic polyurethances, low molecular weight diurethane compounds and fluorinated polyurethanes.These polymers have both polar and non-polar crystals according to theirparallel and antiparallel dipole arrangement.The properties of polyurethane films were investigated using various conventional characterization processes.The structural properties of polyurethanes were studied from IR, X-ray diffraction, ?trdNMR spectroscopies.Thermal characteristics such as glass transition, crystallization transition, and melting temperatures were obtained from the Differential Scanning Calorimeter measurements.The formation and strength of hydrogen bonds in polyurethane between the adjacent N-H and C:O groups of molecular chains were investigated from IR
Author: Ambalangodage Champa Jayasuriya
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W575403674