Search
- Filter Results
- Location
- Classification
- Include attachments
- https://eng.libretexts.org/Bookshelves/Materials_Science/Polymer_Chemistry_(Whisnant)/03%3A_IsomerismIt is a general rule that for a polymer to crystallize, it must have highly regular polymer chains. Highly irregular polymers are almost inevitably amorphous. Polymer chains can have isomeric forms th...It is a general rule that for a polymer to crystallize, it must have highly regular polymer chains. Highly irregular polymers are almost inevitably amorphous. Polymer chains can have isomeric forms that decrease the regularity of the chains. There are three important forms of isomerism in polymers: (1) Structural Isomerism, (2) Sequence Isomerism, and (3) Stereoisomerism.
- https://eng.libretexts.org/Workbench/Materials_Science_for_Electrical_Engineering/10%3A_Polymer_Properties/10.04%3A_Polymer_Chemistry/10.4.06%3A_Polymer_Chemistry-_Morphology/10.4.6.03%3A_Polymer_Chemistry-_Polymer_CrystallinityMost small molecule behavior can be understood in terms of three states: gas, liquid, and solid. Polymers are large molecules with strong intermolecular forces and tangled chains, and do not have a va...Most small molecule behavior can be understood in terms of three states: gas, liquid, and solid. Polymers are large molecules with strong intermolecular forces and tangled chains, and do not have a vapor phase - they decompose at high temperature before forming a vapor. The length of polymer molecules also makes it difficult for the large crystals found in the solid phases of most small molecules to form. Instead solid polymers can be modeled in terms of two phases - crystalline and amorphous.
- https://eng.libretexts.org/Workbench/Materials_Science_for_Electrical_Engineering/10%3A_Polymer_Properties/10.04%3A_Polymer_Chemistry/10.4.01%3A_Polymer_Chemistry-_Chemical_Composition/10.4.1.02%3A_Polymer_Chemistry-_Pendant_GroupsA group attached to the polymer backbone and present in the repeating unit is called a pendant group.
- https://eng.libretexts.org/Workbench/Materials_Science_for_Electrical_Engineering/10%3A_Polymer_Properties/10.04%3A_Polymer_Chemistry/10.4.05%3A_Polymer_Chemistry-_Molecular_Weight_AveragesThe molecular weights of polymers are much larger than the small molecules usually encountered in organic chemistry. Most chain reaction and step reaction polymerizations produce chains with many diff...The molecular weights of polymers are much larger than the small molecules usually encountered in organic chemistry. Most chain reaction and step reaction polymerizations produce chains with many different lengths, so polymers also differ from small molecules in that the polymer molecular weights are average values. You may refer elsewhere for a discussion of the different methods of measuring the average molecular weight of polymers.
- https://eng.libretexts.org/Workbench/Materials_Science_for_Electrical_Engineering/10%3A_Polymer_Properties/10.04%3A_Polymer_ChemistryPolymers are giant molecules (also called macromolecules) that are essential to our existence. They are important chemicals in our bodies (proteins, DNA), in plants (starch, cellulose), and in our eve...Polymers are giant molecules (also called macromolecules) that are essential to our existence. They are important chemicals in our bodies (proteins, DNA), in plants (starch, cellulose), and in our everyday lives (fibers, plastics). Polymers are made by transforming small molecules (monomers) into molecules with very large molecular weights. Although the chemical properties of polymers are similar to those of analogous small molecules, their physical properties are quite different.
- https://eng.libretexts.org/Bookshelves/Materials_Science/Polymer_Chemistry_(Whisnant)/06%3A_Morphology/6.01%3A_Classification_of_PolymersThe most common way of classifying polymers is to separate them into three groups - thermoplastics, thermosets, and elastomers. The thermoplastics can be divided into two types - those that are crysta...The most common way of classifying polymers is to separate them into three groups - thermoplastics, thermosets, and elastomers. The thermoplastics can be divided into two types - those that are crystalline and those that are amorphous.
- https://eng.libretexts.org/Workbench/Materials_Science_for_Electrical_Engineering/10%3A_Polymer_Properties/10.04%3A_Polymer_Chemistry/10.4.06%3A_Polymer_Chemistry-_Morphology/10.4.6.02%3A_Polymer_Chemistry-_Crystallization_TendencySome polymers form more crystalline solids than others. It will be useful for us to relate the tendency to crystallize to the chemical composition and structural details of particular polymers. Six f...Some polymers form more crystalline solids than others. It will be useful for us to relate the tendency to crystallize to the chemical composition and structural details of particular polymers. Six factors favor a polymer with a high percent crystallinity: a regular and symmetrical linear chain, a low degree of polymerization, strong intermolecular forces, small and regular pendant groups, a slow rate of cooling, and oriented molecules.
- https://eng.libretexts.org/Workbench/Materials_Science_for_Electrical_Engineering/10%3A_Polymer_Properties/10.04%3A_Polymer_Chemistry/10.4.08%3A_Polymer_Chemistry-_Transitions/10.4.8.03%3A_Polymer_Chemistry-_The_Glass_TransitionSemi-crystalline solids have both amorphous and crystalline regions. According to the temperature, the amorphous regions can be either in the glassy or rubbery state. The temperature at which the tran...Semi-crystalline solids have both amorphous and crystalline regions. According to the temperature, the amorphous regions can be either in the glassy or rubbery state. The temperature at which the transition in the amorphous regions between the glassy and rubbery state occurs is called the glass transition temperature.
- https://eng.libretexts.org/Workbench/Materials_Science_for_Electrical_Engineering/10%3A_Polymer_Properties/10.04%3A_Polymer_Chemistry/10.4.01%3A_Polymer_Chemistry-_Chemical_Composition/10.4.1.03%3A_Polymer_Chemistry-_Polymerization_ReactionsFor polymerization to take place, the monomers must be capable of being linked to two (or more) other monomer molecules. Most of these reactions can be placed in one of two classifications: chain-reac...For polymerization to take place, the monomers must be capable of being linked to two (or more) other monomer molecules. Most of these reactions can be placed in one of two classifications: chain-reaction polymerization and step-reaction polymerization.
- https://eng.libretexts.org/Bookshelves/Materials_Science/Polymer_Chemistry_(Whisnant)/07%3A_TopologyPolymers are very large molecules with unusual physical properties that depend on the interactions between its chains. An important factor in these interactions is the shape of the chain making up the...Polymers are very large molecules with unusual physical properties that depend on the interactions between its chains. An important factor in these interactions is the shape of the chain making up the backbone of the molecule.
- https://eng.libretexts.org/Bookshelves/Materials_Science/Polymer_Chemistry_(Whisnant)/02%3A_Experimental_Methods/2.02%3A_Tensile_TestingIn a tensile test, a sample of known dimensions (including thickness) is held between two clamps. As the sample is stretched, the force exerted by the instrument and the length (and sometimes cross-se...In a tensile test, a sample of known dimensions (including thickness) is held between two clamps. As the sample is stretched, the force exerted by the instrument and the length (and sometimes cross-sectional area) of the sample are measured.
