Spin measurements, molecular weights

Thus, the results herein support Che conclusion that Improved FOY texturing, as measured by reduced broken filament counts, can be attained via Increases In either the spun yarn amorphous orientation or crystalline content. These desired morphological changes can be achieved via Increased spinning speed, molecular weight, capillary diameter, and reduced melt tonperature. The applicability of these polyester conclusions for other synthetic fibers Is under study and will be reported in the future. 

Zink et al. used a blend of polystyrene (hPS) and its deuterated counterpart (dPS), both of molecular weight 1.95 x 106 (abbreviated 1.95 M). The average volume fraction (4>dPS) of deuterated polystyrene was 30%. The polymers were dissolved in toluene and spin cast on thin silicon wafers (about 10 x 10 mm), the resulting film thickness being about 300 nm. The samples were annealed at 245°C for 8 days, and the measurement of the resulting depth profiles was conducted by NRA using a monoenergetic 700 keV 3He beam. The nuclear reaction employed can be written ... 

Solubility of polymers in tetramethyl ammonium hydroxide aqueous solution was measured by dipping the wafer on which the polymer solution was spin-coated, for 1 min. at 25°C. The prebake was carried out at 90°C for 5min. Sensitivity of resists was measured after the exposure with CA 800(Cobilt) or KrF excimer laser(0.9mJ/cm2/1 pulse). The polymer structure was determined by iH-NMR, 13C-NMR(FX90Q apparatus,JEOL) and 2 Si-NMR. The molecular weight distribution was determined with a Toyo Soda Model 801 gel permeation chromatograph at 40°C. The four columns were connected in series, each packed with G-2000H8x3 and G-400H8(Toyo Soda polystylene gel), respectively. 

Proton NMR relaxation parameters have also been determined for polyethylene ( ) and polyethylene oxide (39) in the melting region. The apparent contradiction between the proton spin-lattice relaxation parameter for a high molecular weight linear polyethylene sample at its melting point, with the relaxation measurements, has previously been pointed out. (17) This discrepancy is still maintained with the more detailed results reported here for both types of polyethylene. For the proton relaxation a small, but distinct, discontinuity is reported at the melting teirperature. (38)... 

The first direct spin-echo diffusion measurement in a polymer melt was reported by McCall, Douglass, and Anderson34) in low-molecular weight polyethylenes. Because of the limitations of the SGSE method the authors found themselves restricted (D > 1(T7 cm2/sec) to molecular weights M < 10 and to temperatures T above 130 °C. They observed an Arrhenius behavior ... 

Creatine kinase is a dimer (molecular weight 82 000), with an active site on each monomer. The activating metal binds to the ATP only, i.e. type I. Spin labelling of the cysteine residue at the active site has allowed distance measurements to Mnu. It appears that Mn remains bound to the a- and /3-phosphoryl groups in ADP. 

---