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The inter-association of poly(methyl methacrylate)/poly(ethylene glycol) (PMMA/PEG) due to hydrogen bonding was investigated in a tetrahydrofuran (THF) system by size exclusion chromatography (SEC) with static light scattering and refractive index detectors. We deduced theoretically that the weight-average molar masses (M w ) at the initial and equilibrium states were different if a complex was formed. Experimental results supported this theoretical analysis. A complex was clearly formed in the PMMA/PEG/THF system. Using a novel method, the principle of minimum error, average stoichiometric coefficients, and equilibrium constant of the complex formation process were determined simultaneously. The M w , composition, and mass of the complex were also quantitatively calculated. The hydrogen bonding interaction of PMMA/PEG in THF was very weak since the magnitude of the equilibrium constants was small and the mass contents of the complexes in the whole blend were low. Supplemental materials are available for ...

In the theory of general temperature modulated differential scanning calorimetry (GTMDSC), the modulated temperature of furnace accords with a random cyclically modulated rule and even a random non-cyclic rule. In this paper, the temperature variation rule of platelike sample in GTMDSC has been drawn with strict mathematical derivation. The obtained analytical result reveals the total variation rule of the platelike sample from its initial equilibrium state to its steady state. With this temperature variation rule, the variation rules of both reversible and irreversible heat flows, temperature lag, internal energy and effective specific heat of the platelike sample have been derived and studied as well. Sinusoidal rule of modulated temperature is only a very special example of general cyclic modulated rules. If the thermal conductivity of the sample is so great that the temperature gradients within the sample can be neglected, in this case the temperature variation rule derived from the fundamental equation of the temperature distribution of GTMDSC is the same as the current TMDSC theories. If the modulated part in temperature equals 0, it reverts to the conventional DSC situation, so all the results in the GTMDSC model derived in this article are automatically suitable for the conventional DSC situation and current TMDSC theories.

In this paper, a novel quasi-isothermal method of measuring sample’s specific heat capacity in temperature modulated differential scanning calorimetry (TMDSC) has been studied. With the strict temperature variation rule of plate-like sample in TMDSC model, the expression of the sample’s surface temperature lag in quasi-isothermal state has been obtained. With this temperature lag rule, sample’s specific heat capacity and its thermal conductivity can be determined at the same time by quasi-isothermal experiment of TMDSC. It has been pointed out here that the obtained heat capacity value of the sample with the quasi-isothermal method is only the average value within the measured temperature interval, and it is true that the bigger the modulated amplitude, the smother the value of heat capacity obtained. In the situation that the specific heat capacity of sample is approximately constant within the measured temperature interval, the quasi-isothermal method of TMDSC is better. If within the measured temperature interval the specific heat capacity of sample is apparently the function of temperature, the best tool to measure the sample’s specific heat capacity is traditional DSC.

In this paper, the temperature variation rule of platelike sample in temperature modulated differential scanning calorimetry (TMDSC) has been drawn with strict mathematical derivation. The obtained analytical result reveals the total variation rule of the platelike sample from its initial equilibrium state to its steady state. With this temperature variation rule, the variation rules of both reversible and irreversible heat flows, temperature lag, internal energy and effective specific heat of the platelike sample have been derived and studied as well. If the thermal conductivity of the sample is so great that the temperature gradients within the sample can be neglected, in this case the temperature variation rule derived from the fundamental equation of the temperature distribution of our TMDSC is the same as the current TMDSC theories. If the modulated amplitude A T s or modulated frequency ω equals zero, it reverts to the conventional DSC situation, so all the results in the TMDSC model derived in this article are automatically suitable for the conventional DSC situation and current TMDSC theories.

It is shown theoretically and experimentally that both the calibration of the molecular weight separation and column dispersion can be evaluated simultaneously by coupling gel chromatograph with low angle light scattering photometer. The experimentally determined variation of the spreading factor with retention volume is quite similar to that obtained by Tung using reverse flow technique. A correction method is given for the lowering of inhomogeneity index printed by the data processor of the on-line GPC-LALLS.

Gel chromatographic, light scattering, viscosimetric and osmotic pressure measurements have been made for high vinyl polybutadiene fractions and whole polymer. Three alternative methods for deducing a monodisperse Mark-Houwink equation from gel chromatographic, light scattering and viscosimetric data of samples with unequal distribution widths are suggested. The monodisperse Mark-Houwink equations obtained by these methods for high vinyl poly(butadiene) are all alike.