Characterization from PMMA measurements

The polymers initiated by BP amines were found to contain about one amino end group per molecular chain. It is reasonable to consider that the combination of BP and such polymers will initiate further polymerization of vinyl monomers. We investigated the photopolymerization of MMA with BP-PMMA bearing an anilino end group as the initiation system and found an increase of the molecular weight from GPC and viscometrical measurement [91]. This system can also initiate the photopolymerization of AN to form a block copolymer, which was characterized by GPC, elemental analysis, and IR spectra. The mechanism proposed is as follows ... 

Column Preparation. PMMA column was prepared using the procedure described by Pawlisch (361. The film thickness was inferred from the values of diffusivities measured with a second PMMA column whose thickness was measured using a destructive characterization technique. The column used in this study had an axial length of 17.78 m, an inner radius of 367 pm, and a film thickness of 5.3 pm. This column was used to measure diffusivities for the PMMA/solvent systems in a temperature interval from 70°C to 160°C. For each temperature, measurements were taken at three different carrier gas flow rates. Replicate measurements were made at each flow rate, and replicate elution curves were obtained at some of the conditions to evaluate reproducibility. 

We further characterized this copolymer mixture by using an Ubbelohde viscometer to measure the solution viscosity of a mixture of D20-PMMA and T12-PMMA in tetrahydrofuran (THF). The formation of supramolecular polymers in the D20-PMMA/T12-PMMA blends provided a higher solution viscosity relative to that of pure PMMA as shown in Figure 2.15 in addition, the viscosity increased upon increasing the concentrations of the copolymers. This supramolecular polymer also could be observed macroscopically—in the form of a gel—from a 1 1 mixture of D20-PMMA/T12-PMMA in THF at a concentration of 30 g/dL at the same concentration, a solution of PMMA, which lacked any specific interpolymer hydrogen-bonding interactions, flowed freely (see the inset to Figure 2.15). 

Bahners et al. [68] investigated the concepts of technical fibers for the special coated fibers to be used for textile solar collectors. The technical fiber made of different polymers (polymethyl methacrylate (PMMA) and polyethylene terepthalate (PET)) were characterized with respect to optical properties relevant for the model. The fibers were coated with a matrix of 5% polyvinyl acetate (PVA) in methanol, into which fluorescent dyes were dispersed. The wave guiding behaviors of the technical fiber over greater lengths were quantitatively analyzed by a logarithmic fit. The measured value was found to divert from the ideal fit at larger fiber lengths. 

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