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C Uriarte

Publications and source records attributed to C Uriarte.

5 recordsLinked to original sources
PubMed2006

The phase behaviour of poly(styrene-co-methacrylic acid)/poly(2,6-dimethyl-1,4-phenylene oxide) by inverse gas chromatography.

The miscibility behaviour of blends of poly(styrene-co-methacrylic acide) (PSMA-12) containing 12% of methacrylic acid with poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) at five different compositions has been studied by inverse gas chromatography (IGC). The adequacy of two types of solvents (solvents and precipitants) has been tested in order to detect the glass transition temperature, T(g). A single T(g) has been observed in PSMA-12/PPO blends containing less than 67wt% of PPO. Two glass transition temperatures appeared, however, in blends containing higher PPO content. The polymer-polymer interaction parameters have been calculated in the molten state (260-280 degrees C), their values being in good agreement with the observed phase behaviour. Moreover, the methods proposed by Farooque-Deshpande and Huang for obtaining the true polymer-polymer interaction parameters have been compared. Finally, the ability of IGC in order to determine T(g)s has been extended to a ternary system, PSMA-12/PPO/EMV4P-8 poly(ethylmethacrylate-co-4-vinylpyridine) which, depending on the composition, gives a single, two and even three T(g)s.

Chromatography, Gas↗
PubMed2002

Polymer-solvent interaction parameters in polymer solutions at high polymer concentrations.

Molecular mass and temperature dependences of the polymer-solvent interaction parameter have been investigated in the extreme interval of high polymer concentration using inverse gas chromatography (IGC). The observed molecular mass dependence has been compared with the predictions of a theoretical model, which emphasises the role of intramolecular contacts in the polymer chain. The model reproduces reasonably well the molecular mass dependence. However, enthalpic and entropic contributions of the interaction parameter, obtained from IGC measurements at different temperatures, exhibit behaviours difficult to explain in the framework of the current models.

Chromatography, Gas↗
PubMed1991

Splenic hydatidosis.

This report is concerned with ten patients treated surgically for a splenic hydatidosis. Splenic echinococcosis represents 3.5% of abdominal hydatid cysts treated in our Service. When splenic hydatidosis was diagnosed, the spleen was the first and only localization of hydatid disease in three cases. One of these patients underwent surgery for a pulmonary cyst four years later. Splenic cysts were asymptomatic in six patients. The most frequent clinical sign of splenic hydatidosis was a painful mass in the left upper abdominal quadrant. Ultrasonography and axial computed tomography (axial C.T.) were the most useful diagnostic tools. The complications arising from splenic hydatidic cysts were infection, rupture in the abdominal cavity and fistulization to the colon. A splenectomy was performed in every case. There was no mortality and morbidity was principally related to the hepatic-associated hydatidosis. It is concluded that splenic involvement is a rare manifestation of hydatid disease but should be looked for in a systematic way in patients with this diagnosis.

Adult↗