Temperature, Polymer Molecular Weight, and Salt Effects on Phase Equilibria of PVP + Formate Salts + Water: Experimental Measurements, Correlations, and Thermodynamic Modeling

2021 ◽  
Author(s):  
Seyyed Mohammad Arzideh ◽  
Maryam Shams Nateri ◽  
Mohsen Pirdashti
Keyword(s):  
Molecular Weight ◽  
Phase Equilibria ◽  
Thermodynamic Modeling ◽  
Experimental Measurements ◽  
Polymer Molecular Weight ◽  
Salt Effects

Crystallization of Isotactic Poly(propylene) in Solution as Followed by Slow Calorimetry

1995 ◽  
Vol 60 (11) ◽  
pp. 1905-1924 ◽  
Author(s):  
Hong Phuong-Nguyen ◽  
Geneviève Delmas
Keyword(s):  
Molecular Weight ◽  
Crystal Growth ◽  
High Temperature ◽  
Heat Of Fusion ◽  
Complete Dissolution ◽  
Polymer Molecular Weight ◽  
Solvent Quality ◽  
Temperature Ramp ◽  
Poly Propylene

Dissolution, crystallization and second dissolution traces of isotactic poly(propylene) have been obtained in a slow temperature ramp (3 K h-1) with the C80 Setaram calorimeter. Traces of phase-change, in presence of solvent, are comparable to traces without solvent. The change of enthalpy on heating or cooling, ∆Htotal, over the 40-170 °C temperature range, is the sum of two contributions, ∆HDSC and ∆Hnetwork. The change ∆HDSC is the usual heat obtained in a fast temperature ramp and ∆Hnetwork is associated with a physical network whose disordering is slow and subject to superheating due to strain. When dissolution is complete, ∆Htotal is equal to ∆H0, the heat of fusion of perfect crystals. The values of ∆Htota for nascent and recrystallized samples are compared. Dissolution is the tool to evaluate the quality of the crystals. The repartition of ∆Htotal, into the two endotherms, reflects the quality of crystals. The crystals grown more rapidly have a higher fraction of network crystals which are stable at high T in the solvents. A complete dissolution, i.e. a high temperature (170 °C or more) is necessary to obtain good crystals. The effect of concentration, polymer molecular weight and solvent quality on crystal growth is analyzed.

Influence of Polymer Molecular Weight on Chain Conformation at the Polystyrene/Silver Interface

Langmuir ◽  
2021 ◽  
Author(s):  
Bianca M. de Lima ◽  
Patrick L. Hayes ◽  
Paula M. Wood-Adams
Keyword(s):  
Molecular Weight ◽  
Chain Conformation ◽  
Polymer Molecular Weight

A Chlorinated Donor Polymer Achieving High‐Performance Organic Solar Cells with a Wide Range of Polymer Molecular Weight

2021 ◽  
pp. 2102413
Author(s):  
Anping Zeng ◽  
Xiaoling Ma ◽  
Mingao Pan ◽  
Yuzhong Chen ◽  
Ruijie Ma ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Solar Cells ◽  
Organic Solar Cells ◽  
High Performance ◽  
Polymer Molecular Weight ◽  
Wide Range
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