KINETICS OF WATER SORPTION IN OKARA AND ITS RELATIONSHIP TO THE GLASS TRANSITION TEMPERATURE

A series of bio-based hydrophobically modified isosorbide dimethacrylates, with para-, meta-, and ortho- benzoate aromatic spacers (ISBGBMA), are synthesized, characterized, and evaluated as potential dental restorative resins. The new monomers, isosorbide 2,5-bis(4-glyceryloxybenzoate) dimethacrylate (ISB4GBMA), isosorbide 2,5-bis(3-glyceryloxybenzoate) dimethacrylate (ISB3GBMA), and isosorbide 2,5-bis(2-glyceryloxybenzoate) dimethacrylate (ISB2GBMA), are mixed with triethylene glycol dimethacrylate (TEGDMA) and photopolymerized. The resulting polymers are evaluated for the degree of monomeric conversion, polymerization shrinkage, water sorption, glass transition temperature, and flexural strength. Isosorbide glycerolate dimethacrylate (ISDGMA) is synthesized, and Bisphenol A glycerolate dimethacrylate (BisGMA) is prepared, and both are evaluated as a reference. Poly(ISBGBMA/TEGDMA) series shows lower water sorption (39–44 µg/mm3) over Poly(ISDGMA/TEGDMA) (73 µg/mm3) but higher than Poly(BisGMA/TEGDMA) (26 µg/mm3). Flexural strength is higher for Poly(ISBGBMA/TEGDMA) series (37–45 MPa) over Poly(ISDGMA/TEGDMA) (10 MPa) and less than Poly(BisGMA/TEGDMA) (53 MPa) after immersion in phosphate-buffered saline (DPBS) for 24 h. Poly(ISB2GBMA/TEGDMA) has the highest glass transition temperature at 85 °C, and its monomeric mixture has the lowest viscosity at 0.62 Pa·s, among the (ISBGBMA/TEGDMA) polymers and monomer mixtures. Collectively, this data suggests that the ortho ISBGBMA monomer is a potential bio-based, BPA-free replacement for BisGMA, and could be the focus for future study.

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AFM Studies of the Molecular Weight Dependence of Lamellar Growth Kinetics of Polymers near the Glass Transition Temperature

Macromolecules ◽

10.1021/ma062717y ◽

2007 ◽

Vol 40 (11) ◽

pp. 4002-4008 ◽

Cited By ~ 7

Author(s):

Yong Wang ◽

Chi-Ming Chan ◽

Yong Jiang ◽

Lin Li ◽

Kai-Mo Ng

Keyword(s):

Molecular Weight ◽

Glass Transition ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Growth Kinetics ◽

Molecular Weight Dependence ◽

Lamellar Growth ◽

Kinetics Of

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Water sorption isotherms and glass transition temperature of spray dried tomato pulp

Journal of Food Engineering ◽

10.1016/j.jfoodeng.2007.07.015 ◽

2008 ◽

Vol 85 (1) ◽

pp. 73-83 ◽

Cited By ~ 184

Author(s):

Athanasia M. Goula ◽

Thodoris D. Karapantsios ◽

Dimitris S. Achilias ◽

Konstantinos G. Adamopoulos

Keyword(s):

Glass Transition ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Water Sorption ◽

Sorption Isotherms ◽

Tomato Pulp ◽

Spray Dried ◽

Water Sorption Isotherms

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Reentanglement Kinetics of Freeze-Dried Polymers above the Glass Transition Temperature

Macromolecules ◽

10.1021/ma300885w ◽

2012 ◽

Vol 45 (16) ◽

pp. 6648-6651 ◽

Cited By ~ 36

Author(s):

Chao Teng ◽

Yun Gao ◽

Xiaoliang Wang ◽

Wei Jiang ◽

Chen Zhang ◽

...

Keyword(s):

Glass Transition ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Freeze Dried ◽

Kinetics Of

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Cure Kinetics of Nanocomposites Prepared From Aqueous Dispersion of Nanoclay

Multifunctional Nanocomposites ◽

10.1115/mn2006-17080 ◽

2006 ◽

Author(s):

Levent Aktas ◽

M. Cengiz Altan

Keyword(s):

Glass Transition ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Storage Modulus ◽

Glass Fibers ◽

Aqueous Dispersion ◽

Cure Kinetics ◽

Temperature Cycle ◽

Waterborne Epoxy ◽

Kinetics Of

The effect of nanoclay on the cure kinetics of glass/waterborne epoxy nanocomposites is investigated. First step in sample preparation involves dispersing Cloisite® Na+, a natural montmorillonite, in distilled water at 70°C with the aid of a sonicator. Then, desired amounts of dicyandiamide and 2-methyl imidazole, serving as cross-linkers, are mixed to the aqueous nanoclay solution. As the mixing continues, Epi-Rez 3522-W-60 waterborne epoxy resin is introduced to the solution and the compound is mixed for an additional 30 minutes. The nanoclay content of this batch is adjusted to be at 2wt%. An identical second batch, which does not comprise nanoclay, is also prepared to serve as the baseline data. Glass/waterborne epoxy prepregs containing 30% glass fibers are prepared from these batches and used to characterize the effects of nanoclay. The evolution of viscoelastic properties during curing are characterized by the APA2000 rheometer. Using the storage and loss moduli profiles during curing, gel time and maximum storage modulus are characterized. Effect of nanoclay on the glass transition temperature is determined by applying an additional temperature cycle following the cure cycle. In addition, mechanical performances of the samples are characterized by three point bending tests. Nanoclay is observed to yield 2-fold higher storage modulus during curing. Rate of curing is measured to be substantially slower for the samples comprising nanoclay. In addition, glass transition temperature improved by 5% to 99°C with the addition of nanoclay compared to 94.5°C for the samples without nanoclay. Flexural stiffness of the samples containing nanoclay is measured to be 20% higher than the samples without nanoclay while the strength remained virtually unaffected.

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