Crosslinked polymers physical crosslinking

Journal of Polymer Science Polymer Physics Edition 39, No.18, 15th Sept.2001, p.2159-67 RHEOLOGICAL PROPERTIES AND FOAM PROCESSABILITY FOR BLENDS OF LINEAR AND CROSSLINKED POLYETHYLENES Yamaguchi M Susuki K-I Tosoh Corp. 

Journal of Polymer Science Polymer Physics Edition 38, No.7, 1st April 2000, p.993-1004 PREDICTION OF THE RADIATION TERM IN THE THERMAL CONDUCTIVITY OF CROSSLINKED CLOSED CELL POLYOLEFIN... 

Journal of Polymer Science Polymer Physics Edition 36, No. 14, Oct. 1998, p.2587-96 THERMAL EXPANSION OF CROSSLINKED CLOSED-CELL POLYETHYLENE FOAMS... 

As in linear polymers, the relative influence of the molecular structure (scale of nanometers and monomers), and the macromolecular structure (crosslink density), on network properties, depends on temperature, as shown in Fig. 10.9. In the glassy state, the physical behavior is essentially controlled by cohesion and local molecular mobility, both properties being mainly under the dependence of the molecular scale structure. As expected, there are only second-order differences between linear and network polymers. Here, most of the results of polymer physics, established on linear polymers, can be used to predict the properties of thermosets. Open questions in this domain concern the local mobility (location and amplitude of the (3 transition). 

Yamaguchi, M. 2001. Rheological properties of linear and crosslinked polymer blends Relation between crosslink density and enhancement of elongational viscosity. Journal of Polymer Science Part B Polymer Physics 39 228-235. 

Liu, S., Zhou, X., 2002. Suface-Crosslinking of a superabsorbent polyacrylate. In International Symposium on Polymer Physics, PP 2002, July 2—6, 2002, Qingdao, China. 

Takashi Sasaki, Shoko Kawagoe, Hajime Mitsuya et al. Glass transition of crosslinked polystyrene shells formed on the surface of calcium carbonate whisker. Journal of Polvmer Science B Polymer Physics. 44(17) 2475-2485, 2006. 

One of the first successful theories of polymer physics was developed for rubber elasticity, and we now briefly outline the essential ideas. It is first assumed that the deformation occurs without changing the sample volume. It is also assumed that the chain segments between crosslinks adopt the Gaussian conformation of an unperturbed coil. The deformation is taken to be affine, i.e. it is the same at the molecular level as at the macroscopic scale. If the sample is deformed by extension ratios Xi, X2 and X3 in three different directions, its dimensions change by these fractional amounts. In an affine deformation the coordinates of the end point of a network chain move by the same factors, i.e. from (x, y, z) to (Xix, kiy, Xsz). 

Bae, Y.H., Okano, T., and Kim, S.W. (1990) Temperature dependence of swelling of crosslinked polyfN.A -aUcyl substituted acrylamides) in water. Journal of Polymer Science, Part B Polymer Physics, 28,923-936. 

The combined use of fractal analysis and cluster models for the structure of the condensed state of crosslinked polymers allows their quantitative treatment on different structural levels, molecular, topological and suprasegmental, to be obtained for the first time and also the interconnection between the indicated levels to be determined. In turn, elaboration of solid-phase crosslinked polymer structure quantitative models allows structure-properties relationships to be obtained for the first time, which is one of the main goals of polymer physics. 

At present analysis of relations between molecular characteristics, supramolecular (suprasegmental) structure parameters and properties of crosslinked polymers is carried out, as a rule, on the qualitative level [27]. It is connected with the complexity of the structure of spatial networks and the quantitative structural model for absence of these polymers [93, 130]. Therefore receiving quantitative relations between the mentioned parameters is an important goal of polymer physics, which is necessary for prediction of the properties of crosslinked polymers. The authors [130] solved this problem by the application of a number of physical concepts synergetics of deformable bodies [47], fractal analysis [92, 93] and the cluster model of the amorphous state structure of polymers [5, 6]. 

Sundar, S., Jang, W., Lee, C., Shul, Y., Han, H. (2005) Crosslinked sulfonated polyimide networks as polymer electrolyte membranes in fuel cells. Journal of Polymer Science Part B Polymer Physics, 43, 2370-2379. 

Stutz H., Illers H., and Mertes J., A Generalized Theory for The Glass Transition Temperature of Crosslinked and Uncrosslinked Polymers , Journal of Polymer Science Part B Polymer Physic, Vol. 28 (1990), pp. 1483-1498. 

Journal of Polymer Science Polymer Physics Edition 34, No.l2, 15th Sept.1996, p.1997-2006 EFFECTS OF THE TYPE OF CROSSLINK ON VISCOELASTIC PROPERTIES OF NATURAL RUBBER... 

Polymer High MW (>10,000) Tg usually < RT Physically crosslinks on cooling Strong Strength Hot tack Viscous loss —> peel force... 

Crosslinked polymers have two or more polymer chains linked together at one or more points other than their ends. The network formed improves the mechanical and physical properties of the polymer. 

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