Dispersity index, copolymerization

Polymers for improving the viscosity index of the copolymethacrylate type can be made into dispersants by copolymerization with a nitrogen monomer. The utilization of these copoiymers allows the quantity of dispersant additives in the formulation to be reduced. 

Fig. 16 Overall conversion versus (a) time and (b) number-average molar mass, M , and poly-dispersity index, A/w/Afn (the line represents the theoretical M ) for the nitroxide-mediated surfactant-free emulsion copolymerizations of methyl methacrylate and styrene in the presence of poly(PEGMA-ct>-MAA-co-styrene)-SGl macroalkoxyamines of different molar masses triangles 9400, and squares 44(X)gmol ) [145]...

Typically, modal dispersion is the dominant factor degrading the bandwidth for multimode optical fibers such as SI POFs. However, as mentioned above, it can be minimized by forming a quadratic refractive index profile in the core region and controlling the propagation speed of each mode. This method was first developed by Nishizawa et al [13, 16] for glass fibers, and subsequently it was adapted to POFs. The first GI POF was reported in 1982 [43]. Initially, the GI profile was formed by copolymerizing two or three kinds of monomers with... 

From a materials point of view, synthesis of two-photon chromophores with even higher two-photon cross-sections is required, so that photopolymerization may be induced by less expensive picosecond, nanosecond and even CW lasers for commercial applications. Also the high 5 materials would enable polymerization simultaneously from multibeam split out of one output of a laser for batch production. Also desired is the use of copolymerization of functional molecules and resins, or doping of other functional components like nanocrystals into resins, so that particular functions could be imparted to polymerized devices. Uniform dispersion of the alien components into the matrix polymer is an important problem to solve. Finally, we need to synthesize functional polymers in other words, instead of doping, we directly induce functional chromophores as a bonded component of monomers or oligomers, so that functions such as light-emission, polarization control, refractive index tuning and so forth become more pronounced. 

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