Crosslinker ratio

Fig. 6. Equilibrium water uptake of P(DEAEA-co-HEMA) samples with 30% (O) and 60% ( ) DEAEA with a crosslinking ratio of 0.003 mol EGDMA/mol monomers in a citrate-borate buffer solution as a function of pH...

Consequently, all experimental results can be explained. Polymers prepared without any additive are graft copolymers (containing perhaps separate BD-AN copolymer) whose grafted chains are crosslinked. Decrease of crosslinking ratio linked possibly with a decrease of grafting ratio leads to a more soluble polymer and conversely, increasing of cross-linking leads to a less soluble polymer. 

TDFRS has been employed for the study of collective and self-diffusion of PS micronetwork spheres (microgels) [63] with crosslink ratios of 1 10,1 20, and 1 50 in toluene from low to high concentrations. 

Figure 20 shows for a concentration series of microgels with a crosslink ratio of 1 20. From the long exposure measurements, the weight average hydro-dynamic radius R )c = 19.0 nm and a distribution width of... 

The equilibrium swelling ratio hf> of PNIPA gels of a specific [monomer]/[crosslinker] ratio depends on the temperature and the concentration... 

The proportion (vol%) of crosslinker used in preparing the imprinted matrix, together with the level and type of porogen control the detailed morphology of the matrix. Pore size, pore distribution, pore volume and surface area are all adjustable, although they are of course closely inter-related. The crosslink ratio or nominal crosslink ratio is defined as the volume % of crosslinker (usually divinylic) employed. 

The spatial variation of crosslinks at bone-forming trabecular surfaces (within 50 gm) in patients with osteoporotic or multiple spontaneous fractures was significantly different from that in normal bone, and the collagen crosslink ratio was higher. It has been hypothesized that the matrix produced in osteoporosis might mature more quickly or undergo post-translational modifications for a longer time than normal bone matrix. 

In contrast to trabecular bone, in the cortical bone of ovx monkeys the mineral content was significantly increased in endosteal regions, while the crystallinity and collagen crosslink ratio remained constant in both periosteal and endosteal tissue [66]. Because these parameters displayed different trends in cortical and trabecular bone, the compositional adaptations may be site-specific. 

The anabolic agents parathyroid hormone (PTH) [66, 71] and nandrolone dec-anoate (ND) [72, 73] have both been shown to stimulate bone formation. PTH caused bone to exhibit compositional characteristics typically associated with younger bone, including a lower mineral matrix ratio, crystallinity and crosslink ratio. In contrast, ND treatment restored those parameters affected by ovariectomy to the level of sham controls in cortical bone, but not in trabecular bone. 

Fig. 15.4.60. C NMR spectra of chloromethylated polystyrene resins of 0-6% crosslink ratio swollen in CDCI3 (see Ref. 97).

The peeling off of a hook fitted with a pressure sensitive adhesive and attached to a ceramic or glass surface can be regarded as a typical example for the creep behavior of an adhesive layer. In particular, thermoplastic adhesives that, to a great extent, also include pressure-sensitive adhesives (Section 5.6) tend to creep under high strain. A reason for this behavior is the time-related failure of individual bonds between the polymer molecules due to the strain imposed from outside. The application of adhesives with a higher crosslink ratio can reduce the adhesive layers tendency to creep. 

PolyHIPE Crosslink ratio Phase volume HjO, % Pore volume, mL/g Surface area, m /g ... 

Nevertheless, in the case of sterically demanding substrates little or no reduction occured, indicating a substrate steieospecificity different from that observed in homogeneous catalysis or when using catalyst precursor belonging to the polymer backbone [32]. For the reduction of acetophenone, crosslinked templated polymers were studied. Optimization of the crosslinking ratio led to the best compromise between activity and selectivity (70% ee for a crosslinking ratio of 50/50 of triisocyanate/diisoc anate) [33, 34]. 

Fig. 1 SEM images of macroporous networks formed by (a) phase separation and (b) cryogelation techniques, (a) PNIPA network Co= 20 % (w/v) BAAm = 30 wt% (with respect to NIP A) rprep=22.5 °C diluent, water. (Reprinted from [14] with permission from Elsevier), (b) PAAm network Tprep = °C Cq= 3 % (w/v) crosslinker ratio (molar ratio of BAAm to AAm) = 1 80. (From [23] with permission of Taylor Francis Group, LLC). Scale bars-. 1 pm (b), 100 pm (b)...

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