Decreasing cross-linking

The effect of hydrophobicity of the polymer on the permeability of poly(2-hydroxyethyl methacrylate (HEMA)-co-methacrylic acid (MAAc) hydrogels was studied [12], The hydrophobicity was controlled by copolymerization with butyl methacrylate (BMA). The dependence of permeability on pH increased as the hydrophobicity increased even though the rate of diffusion decreased. Cross-link density of the hydrogel also contributed to pH-dependent permeability. 

The absorption of moisture critically affects other important resin properties, particularly those associated with low-dielectric and thermomechanical applications. Results of a 96-h boiling water immersion test are presented in Table 2.2. The moisture absorbed decreased substantially with fluoromethylene chain length from n = 3 to n = 6, followed by only modest decreases for n = 8 and 10. This latter behavior was somewhat unexpected and may be the effect of decreased cross-link density counteracting the increased fluorine content. These 100°C measurements are just above the glass transition and the situation may be different at room temperature. These measurements are in progress. 

Analytical Properties Separation of three- and four-member methylated polycyclic aromatic hydrocarbons (PAHs) on basis of length-to-breadth ratio (l/b) as l/b increases, retention time decreases cross-linking increases retention times, separation of methylcrypene isomers Reference 18... 

Ehlers-Danlos V and Decreased cross-linking Skin and joint hyperextensibility cutis laxa... 

Table 5-14 describes the describes the influence of cross-link density in different keratin fibers on diffusion rate. These data clearly show that the rate of diffusion into keratin fibers decreases with increasing cystine content and therefore with increasing cross-hnk density. One may conclude that reactions that decrease the cross-link density of hair (e.g., bleaching) will lead to hair that is more rapidly penetrated, and its penetrability will increase with increased bleaching. Decreasing cross-link density obviously increases the rate of transcellular diffusion. 

The effect of these is to decrease cross-linking density in the cured resin due to the lower number of amidic or aminic groups in their molecules. Thus in resin segments where... 

Reference [60] describes the influence of various factors on RID formation in polymeric planar structures (forepolymeric matrix from DAIP - maneic anhydride (MA) - penetrant -MMA MA is injected into the matrix composition for decreasing cross-link frequency, which reduces mechanical stresses occurring at diffusion). 

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