Synthesis and Characterization of PET-Based Liquid Crystalline Copolyesters Containing 6-Oxynaphthalene-2-carboxylate and 6-Oxyanthracene-2-carboxylate Units

Hibbs, Michael; Vargas, Marian; Holtzclaw, Jeremy; Rich, Wendy; Collard, David M.; Schiraldi, David A.

doi:10.1021/ma034425s

Cited by 6 publications

(4 citation statements)

References 46 publications

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“…Figure 3 confirms the liquid crystal nature of the system containing the least amount of OB, i.e., 30 wt %. Most studies emphasize that the minimum amount needed to attain this phase is 35%, as suggested by Hibbs et al29…”

Section: Resultsmentioning

confidence: 99%

Evaluation of the flexural strength of dual‐cure composite resin cements

2013

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The aim of this study was to evaluate of flexural strength of some adhesive resin cements. Three dual-cure composite resin cements (Nexus 3; Variolink II, Panavia F) were prepared. The manufacturer's mixing directions for the cements were followed. Adhesive resin cement was mixed, placed in the rectangular portion of the mold. Fifteen specimens were prepared for each cements. The cements were light-activated with light lamp for 40 s on both and top and bottom surfaces. The each cement specimens were divided into three groups according to time of storage and stored in distilled water for 24 h, 15, and 30 days. Total 45 specimens were stored at 37°C (98.6 0F) in distilled water for 24 h, 15, and 30 days prior to tests. The flexural strength was tested wıth a universal testing machine at a crosshead speed of 0.5 mm/min (0.02 in.) The maximum load was recorded as MPa. The results were analyzed by Analysis of Variance and Duncan test. The Panavia F resin cements content Bisphenol A was showed the highest flexural strength (80.80 MPa) (11.71 ksi) for 24 h. The lowest flexural strength was observed in Nexus 3 (51.00 MPa) (7.39 ksi). It was found significant interaction of material and time (p < 0.05). The types of cement and time of storage was statistically significant on the flexural strengths (p < 0.001).

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Section: Resultsmentioning

confidence: 99%

Evaluation of the flexural strength of dual‐cure composite resin cements

2013

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“…The standard drug streptomycin (10 µg) was used as a positive reference having an endothermic melting peak (T m ) at 105°C with the corresponding enthalpy (∆Hm) of 88.67J/g. [18] BIOLOGICAL ACTIVITIES Antibacterial property(disc-diffusion method)…”

Section: Viscosity Measurementsmentioning

confidence: 99%

Untitled

Rais¹

2018

AJP

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Aim: To synthesise random copolyesters containing chalcone moiety in the main chain, their characterization and biological activity. Material and Methods: A series of eight random copolyesters were synthesized by the polycondensation of a chalcone diol with two aromatic diacid chlorides and four aliphatic diacid chlorides. The two aromatic diacid chlorides used were terephthaloyl chloride and isophthaloyl chloride. The aliphatic diacid chlorides used were adipoyl chloride, oxalyl chloride, glutaryl chloride, and succinyl chloride. The chalcone diol was synthesized by acid catalyzed Claisen-Schmidt reaction. Results and Discussions: These copolyesters were characterized by qualitative solubility tests and viscosity measurements. The microstructure of the repeating units available in the copolyester main chain was established by Fourier transform infrared, 1 H-nuclear magnetic resonance (NMR), and 13 C-NMR spectroscopic techniques. DSC was apply to study thermal analysis. The well diffusion method was employed to establish the biological efficacy of these eight copolyesters by involving Grampositive and Gram-negative bacteria. Conclusion: The presented work reports random copolyester preparation by polycondensation method and viscosity measurements tells about that the prepared compounds are of high molecular weight. others like FTIR, NMR, Solubility measurements and DSC characterize them. Biological properties was also studied.

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“…Most studies emphasize that the minimum amount needed to attain this phase is 35%, as suggested by Hibbs et al 29 …”

Section: Optical Polarizing Microscopymentioning

confidence: 99%

Synthesis of liquid crystalline polymers from polyethylene terephthalate and 4‐acetoxybenzoic acid: A kinetic study

Bishara

Al‐Mulla

Al‐Roomi

et al. 2011

J of Applied Polymer Sci

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Liquid crystalline polymers (LCPs) have been synthesized from polyethylene terephthalate (PET) and 4-acetoxybenzoic acid (OB) through melt step-growth polymerization. The presence of liquid crystalline texture is first examined using optical polarizing microscopy. The thermal durability of the developed systems is studied through thermogravimetric analysis. The kinetics of the polymerization processes is analyzed. The effectiveness of three catalysts commonly used in polyesterification is investigated. The effect of reaction temperature is also examined. The progress of polycondensation reactions over time takes a nonlinear behavior of slight sigmoidal shape, irrespective of whether or not the reaction is catalyzed. Simple second and third order equations, along with a nonlinear model, are used to determine the kinetic parameters characterizing these reactions. The rate of reaction is enhanced when the reaction temperature is increased. Overall, second-order kinetics well describes the polymerization reactions when the data set is divided into two regions. Antimony trioxide induces a more visible enhancement to the rate of reaction, compared to zinc acetate and sodium acetate. The presence of a catalyst generally increases the reaction activation energy. This indicates that entropy factors outweigh the increase in activation energy and drive the catalyzed reactions to completion.

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Synthesis and Characterization of PET-Based Liquid Crystalline Copolyesters Containing 6-Oxynaphthalene-2-carboxylate and 6-Oxyanthracene-2-carboxylate Units

Cited by 6 publications

References 46 publications

Evaluation of the flexural strength of dual‐cure composite resin cements

Evaluation of the flexural strength of dual‐cure composite resin cements

Untitled

Synthesis of liquid crystalline polymers from polyethylene terephthalate and 4‐acetoxybenzoic acid: A kinetic study

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