Poly(glycerol sebacate) Thermal Properties Quiz

<p>The temperature at which the crystalline regions of the polymer melt. (B)</p> Signup and view all the answers

<p>Measuring the mass loss in 12PBS. (D)</p> Signup and view all the answers

<p>Biomedical hydrogels (C)</p> Signup and view all the answers

<p>Polyethers (C)</p> Signup and view all the answers

<p>Poly(esters) (C)</p> Signup and view all the answers

<p>Both resorbable and permanent polymers (A)</p> Signup and view all the answers

<p>Protein adsorption on surfaces (C)</p> Signup and view all the answers

<p>Polysaccharides (B)</p> Signup and view all the answers

<p>Mechanical properties (B)</p> Signup and view all the answers

<p>Trujillo (B)</p> Signup and view all the answers

<p>Tension forces (B)</p> Signup and view all the answers

<p>Transparency (D)</p> Signup and view all the answers

<p>Physicochemical properties of polymer materials (C)</p> Signup and view all the answers

<p>February 4th, 11th and 18th, 2025 (A)</p> Signup and view all the answers

<p>Lubricity (C)</p> Signup and view all the answers

<p>Degradability (C)</p> Signup and view all the answers

<p>Urethane linkage (C)</p> Signup and view all the answers

<p>Tunable physicochemical properties via monomer composition. (B)</p> Signup and view all the answers

<p>Amines (B)</p> Signup and view all the answers

<p>They are generally thermoplastic and easily processed as melts. (A)</p> Signup and view all the answers

<p>Failures in long-term implants (D)</p> Signup and view all the answers

<p>Glycerol and sebacic acid (D)</p> Signup and view all the answers

<p>Sintering (B)</p> Signup and view all the answers

<p>0.01 - 1.5 MPa (A)</p> Signup and view all the answers

<p>Months to 2 years (A)</p> Signup and view all the answers

<p>0.4 - 0.7 MPa (C)</p> Signup and view all the answers

<p>An elastomer (A)</p> Signup and view all the answers

<p>Polycondensation and crosslinking (C)</p> Signup and view all the answers

<p>Nitrogen atmosphere (B)</p> Signup and view all the answers

<p>Vacuum environment (D)</p> Signup and view all the answers

<p>Hydrogen bonding between urethane groups. (B)</p> Signup and view all the answers

<p>They exhibit rubbery and amorphous characteristics. (D)</p> Signup and view all the answers

<p>To act as physical cross-links providing elastomeric behavior. (C)</p> Signup and view all the answers

<p>Heating the material above the hard segment melting transition. (D)</p> Signup and view all the answers

<p>It reacts with a polyol to form NCO-terminated prepolymers. (B)</p> Signup and view all the answers

<p>TPUs have a linear and uncrosslinked structure, while thermosets have a chemically crosslinked 3D network. (B)</p> Signup and view all the answers

<p>Creating a prepolymer with –NCO ending chains using excess diisocyanate. (B)</p> Signup and view all the answers

<p>TPUs can be thermo-reprocessed, while thermosets cannot. (D)</p> Signup and view all the answers

<p>A short diol, such as 1,4 butanediol (BDO), used to link prepolymers. (C)</p> Signup and view all the answers

<p>It is derived from rigid diisocyanates and chain extenders. (B)</p> Signup and view all the answers

<p>They are prepared by mixing polyols and polyisocyanates with at least one monomer with functionality &gt; 4. (A)</p> Signup and view all the answers

<p>They have a chemically crosslinked 3D network structure. (A)</p> Signup and view all the answers

<p>To have –NCO ending chains, which then react further. (C)</p> Signup and view all the answers

Polymers that break down over time in the body, often used for temporary implants or drug delivery.

Polymers that remain stable in the body for extended periods, suitable for long-term medical devices.

A breakdown mechanism where water molecules break down the polymer chain through chemical reactions, leading to smaller fragments.

Polymers that undergo a chemical reaction with water molecules, leading to their gradual breakdown in the body.

Polymers that resist degradation in the body, preserving their original structure over time.

Polymers derived from petroleum and other natural sources, often used for various applications.

The rate at which a polymer breaks down in the body, influenced by its chemical composition.

The backbone of a polymer is the central chain of repeating units that forms the basis of its structure.

The chemical structure of the repeating units that make up a polymer, determining its properties and degradation rate.

The process of breaking down a polymer into smaller fragments, typically through chemical reactions.

A material's resistance to breaking down or decomposing over time, often measured by mass loss.

A polymer made from glycerol and sebacic acid. Known for its flexibility and biocompatibility.

The temperature at which a material transitions from a rigid, glassy state to a more flexible, rubbery state.

A technique used to measure the thermal properties of materials, showing how they behave when heated or cooled.

A material that exhibits both crystalline and amorphous regions, meaning it has ordered and disordered structures.

A region within a thermoplastic polyurethane (TPU) where polymer chains are tightly packed due to hydrogen bonding between urethane and urea groups. These domains act as physical cross-links that resist deformation under stress.

Regions in a thermoplastic polyurethane (TPU) that are primarily made up of flexible chains, often with lower glass transition temperatures (Tg). They provide elasticity and flexibility to the material.

These are interactions between molecules where a hydrogen atom is shared between two electronegative atoms, such as oxygen or nitrogen. In TPUs, this occurs between urethane and urea groups, creating strong intermolecular forces that lead to the formation of hard segments.

A process that involves heating a thermoplastic polyurethane (TPU) above its hard segment melting transition temperature. This breaks the physical cross-links in the hard segments, making the polymer more fluid and allowing it to be processed (e.g., molded or extruded).

The relative amounts of hard and soft segments in a thermoplastic polyurethane (TPU) directly influence its mechanical properties. A higher proportion of hard segments results in a stiffer and stronger material, while a higher proportion of soft segments provides greater elasticity and flexibility.

The ability of a material to resist stretching or elongation under tensile forces. It is a measure of how much force is required to deform the material.

The ability of a material to resist compression forces, or being squeezed or pushed together. It's how much force is needed to change its volume.

The ability of a material to withstand repeated cycles of loading and unloading without breaking. It's how many times it can be stressed before it fails.

The strength of a material in resisting forces acting perpendicular to a surface. Imagine a rope tied around a post, pulling on it.

The ability of a material to resist forces that tend to cause it to slide or deform in parallel directions. It's how much force it takes to make the material slip.

The ability of a material to resist wear and tear from rubbing or sliding against another surface. Think of the friction between your shoes and the floor.

The ability of a material to allow light to pass through it. Think of a window letting sunlight in.

The ability of a material to reduce friction between moving surfaces. Think of oil in an engine, preventing parts from rubbing together.

Poly(glycerol sebacate) is a biodegradable, biocompatible, and resorbable polyester used in various biomedical applications.

PGS is synthesized through a two-step process involving polycondensation followed by crosslinking.

Glycerol and sebacic acid are the monomers used in the synthesis of PGS. These monomers are derived from plant sources.

Polycondensation is the first step in PGS synthesis. It involves the reaction of glycerol and sebacic acid to form a prepolymer.

Crosslinking is the second step in PGS synthesis. It involves the formation of a 3D network structure by the reaction of prepolymer chains.

The crosslinking step is performed in vacuum to remove water molecules and promote the formation of a strong network structure.

The degree of esterification (DE) is a measure of the extent of the reaction between glycerol and sebacic acid during PGS synthesis.

DE increases during the polycondensation step and reaches a plateau during the crosslinking step.

The temperature and time of the polycondensation step influence the DE and the properties of the final PGS material.

PGS is a biodegradable polymer that degrades in the body through hydrolysis, breaking down into monomers that are then absorbed and metabolized.

Polyurethanes (PUs) are materials that can be classified into two main categories: thermosets and thermoplastics. They are typically formed through the reaction of polyols and polyisocyanates.

Thermoplastic PUs (TPUs) are linear, uncrosslinked structures that can be melted and reshaped without degrading. They are usually made by a two-step process involving prepolymer synthesis and chain extension.

Thermoset PUs are characterized by their 3D crosslinked network structure. This makes them strong and rigid, but also unable to be melted or reshaped.

Prepolymer synthesis involves reacting a polydiol with an excess of diisocyanate, resulting in a molecule with –NCO groups at its ends. This prepolymer is then further extended with a chain extender.

The final stage of TPU production involves adding a chain extender, such as 1,4 Butanediol (BDO), to the prepolymer. This creates longer, linear chains, contributing to the TPU's flexibility.

Thermoset PUs are typically produced by mixing polyols and polyisocyanates in a single step, leading to the formation of a 3D crosslinked network. This process often includes the use of surfactants and blowing agents for foam formation.

The hard segment in TPUs is typically composed of a rigid diisocyanate and a chain extender. This segment contributes to the material's stiffness and strength.

The soft segment of TPUs is mainly composed of a flexible and long diol. This segment contributes to the material's flexibility and elasticity.