Detail of "1142-39-8"

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Thermodynamic miscibility in polymer-liquid crystal blends

Thermodynamic miscibility in polymer-liquid crystal blends. Belfiore, Laurence A. (Dep. Agric. Chem. Eng., Colorado State Univ.In this study， 108113-57-1 and 25322-68-3 are also used., Fort Collins, CO 80523, USA). Polym. Prepr. (Am. Chem. Soc., Div. Polym. Chem.), 28(1), 158-9 (English) 1987. CODEN: ACPPAY. ISSN: 0032-3934. DOCUMENT TYPE: Journal CA Section: 37 (Plastics Manufacture and Processing) Section cross-reference(s): 75 The phase behavior of 2 polymer-liq. crystal blends was investigated in the solid and molten states. The low-mol.-wt. nematogen, p-pentyloxycinnamic acid (I) [108113-57-1], exhibited partial concn.-dependent miscibility with amorphous bisphenol A polycarbonate, based on the depression of the blend glass temp. for liq. crystal concns. in the range of 0-15 wt.%. DSC indicated the presence of 32 phases for higher concns. of I, based on the appearance of 1st-order thermodn. transitions in the DSC thermograms which were characteristic of the liq. crystal component. Solid-state NMR tests confirmed the DSC results. Chem. shift perturbations were obsd. for I in its polymer-mixed state. Blends of semicryst. polyethylene glycol (II) [25322-68-3] and p-hexyloxybenzoic acid (III) [1142-39-8] were almost completely immiscible below the melting temp. of II. Calorimetry indicated that the 1st-order thermodn. transition temps. of both components in their undild. states were unaffected by the mixing process. Solid-state NMR at ambient temp. supported the DSC results. In contrast to the phase sepn. obsd. at lower temps., group-contribution predictions suggested that all mixts. of II and III were thermodynamically stable in the equil. molten state above 160°. .

Hydrogen bonding in liquid crystalline phases of p-n-alkoxybenzoic acids

Hydrogen bonding in liquid crystalline phases of p-n-alkoxybenzoic acids. Plass, Monika (Inst. Phys. Chem., Martin-Luther-Univ.Chemicals with cas numbers 2493-84-7 and 1142-39-8 also play role., Halle D-06120, Germany). Zeitschrift fuer Physikalische Chemie (Munich), 194(2), 223-230 (English) 1996 Oldenbourg. CODEN: ZPCFAX. ISSN: 0044-3336. DOCUMENT TYPE: Journal CA Section: 75 (Crystallography and Liquid Crystals) Section cross-reference(s): 69, 73 IR measurements on alkoxybenzoic acids of varying length in the alkyl chain (n = 4-10) were made as a function of temp. The change of the equil. between monomeric, open dimeric, and cyclic dimeric alkoxybenzoic acids was studied using the intensity of the nonassocd. OH signal. In the intensity-temp. plot it was found that the slope changes in the different phases. Conclusions regarding the different behavior of the compds. were made based on changes in the intermol. interactions of the phases due to the increasing mol. mobility with increasing temp. From our IR measurements an odd-even effect can be deduced. The enthalpy value of the monomer-dimer equil. in the nematic phase was higher than in smectic C phases. .