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That is, is the total number of polymer segments (monomers) in the solution, so is the number of nearest-neighbor sites to all the polymer segments. Multiplying by the probability ϕ 1 {\displaystyle \phi _{1}} that any such site is occupied by a solvent molecule, [6] we obtain the total number of polymer-solvent molecular interactions.
The Flory–Fox equation relates the number-average molecular weight, M n, to the glass transition temperature, T g, as shown below: =, where T g,∞ is the maximum glass transition temperature that can be achieved at a theoretical infinite molecular weight and K is an empirical parameter that is related to the free volume present in the polymer sample.
Therefore, this polymer relies solely on physical anchor points. When heated up to Tg, the material abruptly changes from a rigid state to a tapered state (softens). To achieve the effect, the shape must be changed rapidly to avoid rearrangement of the segments of the polymer chains and immediately cool the material also very rapidly below Tg.
[1] [2] Polymers can crystallize upon cooling from melting, mechanical stretching or solvent evaporation. Crystallization affects optical, mechanical, thermal and chemical properties of the polymer. Crystallization affects optical, mechanical, thermal and chemical properties of the polymer.
[1] [better source needed] The practical significance of tacticity rests on the effects on the physical properties of the polymer. [ not verified in body ] The regularity of the macromolecular structure influences the degree to which it has rigid, crystalline long range order or flexible, amorphous long range disorder.
In IUPAC nomenclature of chemistry, a pendant group (sometimes spelled pendent) or side group is a group of atoms attached to a backbone chain of a long molecule, usually a polymer. Pendant groups are different from pendant chains, as they are neither oligomeric nor polymeric. [2] For example, the phenyl groups are the pendant groups on a ...
Poly(p-phenylene oxide) (PPO), poly(p-phenylene ether) (PPE), poly(oxy-2,6-dimethyl-1,4-phenylene), often referred to simply as polyphenylene oxide, is a high-temperature thermoplastic with the general formula (C 8 H 8 O) n. It is rarely used in its pure form due to difficulties in processing.
n O(C 6 H 5) 2 + n SO2Cl2 → {[O(C 6 H 4) 2]SO 2} n + 2n HCl. This route is complicated by the formation of isomers arising from both para- and ortho- substitution. Furthermore, cross-linking was observed, which strongly affects the mechanical properties of the polymer. [7] [4] This method has been abandoned.