BLOCCO 7
Polyurethanes are employed for medical devices such as vascular grafts and heart valves due to their good physical properties and this characteristic.
Biocompatibility
The type of molecular weight where larger molecules contribute more to the viscosity.
Viscosity-average molecular weight
The number, n, of repeating units in a polymer chain.
Degree of Polymerization
Polymers classified by molecular forces that possess strong intermolecular forces like hydrogen bonding, leading to close packing of chains.
Fibers
A polymer made by linking only one type of monomer.
Homopolymer
The type of molecular weight that is very sensitive to changes in the weight-fractions of low molecular weight species.
Number-average molecular weight
A type of copolymer where two different monomers (A and B) alternate along the chain (e.g., A-B-A-B).
Alternating copolymer
For amorphous solids, this property is not definite, and the material simply becomes less and less viscous as the temperature is raised.
Melting temperature
A large molecule composed of many smaller repeating units.
Polymer
Man-made polymers which include fibers like Teflon and Dacron, synthetic rubbers, plastics, and PVC.
Synthetic polymers
A polymer structure where monomer units are arranged in a single, continuous chain without branches.
Linear polymer
The smaller repeating units that bond together to form a polymer.
Monomers
A polyamide known for its ability to be spun into fibers that have five times the tensile strength of steel.
Kevlar
The temperature below which a polymer behaves in an increasingly brittle manner.
Glass transition temperature
Polymers with extensive cross-links between different polymer chains, forming a three-dimensional network of bonds.
Thermosetting polymers
A brand name for Polyethylene terephthalate (PET) that is a common thermoplastic polymer, often used for synthetic fibers.
Dacron
Starch, cellulose, protein, silk, wool, and natural rubber are examples of this type of polymer based on origin.
Natural polymers
The common abbreviation for Polyethylene terephthalate, a polyester used for synthetic fibers and bottles.
PET
Polymers derived from naturally occurring polymers by chemical modifications.
Semi-synthetic polymers
Nylon 6.6, formed from adipic acid and hexamethylene diamine, is an example of this type of polymer.
Polyamide
The type of molecular weight that is very sensitive to changes in the number of large molecules, often measured by light scattering.
Weight-average molecular weight
Polymers classified by molecular forces that are held by the weakest intermolecular forces and can retract to their original position after force is released.
Elastomers
The type of polymerization where two different monomers combine with the loss of a small molecule (e.g., H₂O, HCl, CH₃OH).
Condensation polymerization
The type of polymerization formed by the repeated additions of monomeric units, where the monomers are unsaturated compounds.
Addition polymerization
A long-term issue that polyurethanes suffer from in living tissues, where they can be degraded by water.
Hydrolytic degradation
A polymer formed by joining two different types of monomers in the same polymer chain.
Copolymer
Polymers with intermolecular forces intermediate between elastomers and fibers, having no cross-links, and can be molded on heating.
Thermoplastic polymers
For a polymer that is monodisperse (chains all the same length), what is the value of its Degree of Polydispersity (PD)?
1
The property of a polymer that indicates the uniformity of its molecular weight distribution.
Degree of Polydispersity
The process by which monomers bond together to form a polymer.
Polymerization