Distinguishing relaxation dynamics in transiently crosslinked polymeric networks

2017 ◽  
Vol 8 (35) ◽  
pp. 5336-5343 ◽  
Author(s):  
Cindy Soo Yun Tan ◽  
Gillie Agmon ◽  
Ji Liu ◽  
Dominique Hoogland ◽  
Emma-Rose Janeček ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Mechanical Behaviour ◽  
Polymeric Materials ◽  
Relaxation Dynamics ◽  
Polymer Molecular Weight ◽  
Polymeric Networks ◽  
And Control

Polymeric materials based on reversible non-covalent associations possess diverse mechanical behaviour, which can be orthogonally accessed through polymer molecular weight and control over physical crosslinks.

scholarly journals Gold Nanoparticles Size Design and Control by Poly(N,N′-diethylaminoethyl methacrylate)

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Norma A. Cortez-Lemus ◽  
Angel Licea-Claverie ◽  
Francisco Paraguay-Delgado ◽  
Gabriel Alonso-Nuñez
Keyword(s):  
Molecular Weight ◽  
Gold Nanoparticles ◽  
Ph Value ◽  
Polymer Molecular Weight ◽  
Polar Solvents ◽  
Molecular Weights ◽  
Solvent Type ◽  
Acidic Conditions ◽  
And Control

Poly(N,N′-diethylaminoethyl methacrylate) (PDEAEM) with different molecular weights was used to stabilize gold nanoparticles (AuNPs) obtained byin situreduction of tetrachloroauric acid using citrates under acidic conditions and in organic/alcoholic medium. The influence of the pH value on gold nanoparticle size in the presence of PDEAEM was investigated. Results show that the pH of the reacting mixture has a dramatic effect on the size, polydispersity, and morphology of the resulting AuNPs. Moreover, the size of the nanoparticles (NPs) may be modified by changing the solution’s pH or by changing the solvent type. Electron microscope images showed that the sizes of AuNPs coated with PDEAEM were not sensitive to the variation of the polymer molecular weight in the range between 9000 and 29300 g/mol; however their aggregation behavior depended strongly on the polymer molecular weight as revealed by dynamic light scattering studies. AuNPs stabilized with PDEAEM (AuNP@PDEAEM) are stable in water at acidic pH and in organic polar solvents.

Method for Structural Characterization of High Polymeric Networks by an Osmotic Pressure Technique

1968 ◽  
Vol 41 (2) ◽  
pp. 432-436
Author(s):  
R. D. Seeley ◽  
P. B. Rand
Keyword(s):  
Molecular Weight ◽  
Osmotic Pressure ◽  
Polymer Network ◽  
Polymeric Materials ◽  
Polymer Systems ◽  
Polymeric Networks ◽  
A Value ◽  
Solvent Systems ◽  
Solute Component

Abstract An apparatus was designed to measure the osmotic pressure of solvent-polymer systems. The method is unique in that semirigid polymers may be incorporated as the solute component without specimen fissures occurring from excessive solvent dilative action. The advantages of this technique are: high polymeric materials both elastomeric and plastic can be structurally characterized by the same technique; the calculated effective molecular weight of the polymer network will reflect a value consistent with the polymer's performance characteristics; and the method is only restricted to lyophilic polymer—solvent systems.

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.

scholarly journals The Influence of Polymer Molecular Weight in Lamellar Gels Based on PEG-Lipids

1998 ◽  
Vol 75 (1) ◽  
pp. 272-293 ◽  
Author(s):  
Heidi E. Warriner ◽  
S.L. Keller ◽  
Stefan H.J. Idziak ◽  
Nelle L. Slack ◽  
Patrick Davidson ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Polymer Molecular Weight
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