scholarly journals Study of poly(bisphenol A carbonate) relaxation kinetics at the glass transition temperature

2007 ◽  
Vol 43 (1) ◽  
pp. 249-254 ◽  
Author(s):  
L. Delbreilh ◽  
E. Dargent ◽  
J. Grenet ◽  
J.-M. Saiter ◽  
A. Bernès ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Bisphenol A ◽  
Relaxation Kinetics

scholarly journals Studies on the Modification of Commercial Bisphenol-A-Based Epoxy Resin Using Different Multifunctional Epoxy Systems

2021 ◽  
Vol 2 (2) ◽  
pp. 419-430
Author(s):  
Ankur Bajpai ◽  
James R. Davidson ◽  
Colin Robert
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Bisphenol A ◽  
Epoxy Resin ◽  
Tensile Fracture ◽  
Chemical Structures ◽  
Amino Phenol ◽  
Epoxy Systems

The tensile fracture mechanics and thermo-mechanical properties of mixtures composed of two kinds of epoxy resins of different chemical structures and functional groups were studied. The base resin was a bi-functional epoxy resin based on diglycidyl ether of bisphenol-A (DGEBA) and the other resins were (a) distilled triglycidylether of meta-amino phenol (b) 1, 6–naphthalene di epoxy and (c) fluorene di epoxy. This research shows that a small number of multifunctional epoxy systems, both di- and tri-functional, can significantly increase tensile strength (14%) over neat DGEBA while having no negative impact on other mechanical properties including glass transition temperature and elastic modulus. In fact, when compared to unmodified DGEBA, the tri-functional epoxy shows a slight increase (5%) in glass transition temperature at 10 wt.% concentration. The enhanced crosslinking of DGEBA (90 wt.%)/distilled triglycidylether of meta-amino phenol (10 wt.%) blends may be the possible reason for the improved glass transition. Finally, the influence of strain rate, temperature and moisture were investigated for both the neat DGEBA and the best performing modified system. The neat DGEBA was steadily outperformed by its modified counterpart in every condition.

scholarly journals Hydrophobically Modified Isosorbide Dimethacrylates as a Bisphenol-A (BPA)-Free Dental Filling Material

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2139
Author(s):  
Bilal Marie ◽  
Raymond Clark ◽  
Tim Gillece ◽  
Seher Ozkan ◽  
Michael Jaffe ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Flexural Strength ◽  
Bisphenol A ◽  
Water Sorption ◽  
Triethylene Glycol ◽  
Filling Material ◽  
Hydrophobically Modified ◽  
Free Replacement

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.

Curing, Thermal and Mechanical Properties of Liquid Crystalline p-SBPEPB/BPAER/DDE System

2011 ◽  
Vol 239-242 ◽  
pp. 3253-3256 ◽  
Author(s):  
Li Huo ◽  
Jun Gang Gao ◽  
Yong Gang Du
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Impact Strength ◽  
Bisphenol A ◽  
Liquid Crystalline ◽  
Curing Agent ◽  
Thermal And Mechanical Properties ◽  
Component System

The curing, thermal and mechanical properties of bi-component system for bisphenol A epoxy resin (BPAER) modified by liquid crystalline Sulfonyl bis(4,1-phenylene)bis[4-(2,3-epoxypro pyloxy)benzoate] (p-SBPEPB), with 4,4'-diaminodiphenyl ether (DDE) as a curing agent, were investigated. The effect of the different liquid crystalline contents and the heating rate on curing reaction was discussed. The results show that the curing peak temperature decreases, curing rate increases, the glass transition temperature (Tg)and impact strength all increase with adding of liquid crystalline p-SBPEPB when the content is not over 8wt%.

Preparation of RPSL-02 Type Photosensitive Resin for Stereolithography Material and Investigation on its some Properties

2012 ◽  
Vol 252 ◽  
pp. 224-227
Author(s):  
Bi Wu Huang ◽  
Kuan Zhou ◽  
Chong Deng ◽  
Wei Qing Chen
Keyword(s):  
Weight Loss ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Bisphenol A ◽  
Raw Materials ◽  
Triethylene Glycol ◽  
Divinyl Ether ◽  
Photosensitive Resin

RPSL-02 type photosensitive resin for stereolithography material was prepared with 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate (UVR 6110), bisphenol A type epoxy diacrylate (EA-612), trimethyolpropane triacrylate (TMPTA), polycaprolactone polyol (polyol-0301), triethylene glycol divinyl ether (DVE-3), benzil dimethyl ketal (Irgacure651) and a mixture of triarylsulfonium hexafluoroantimonate salts (UVI-6976) as raw materials. Some properties of the photosensitive resin were investigated. The viscosity of the photosensitive resin at 30°C was 395mPa.S, The glass transition temperature (Tg ) of the UV-cured specimen was 52°C, and the weight loss of the UV-cured specimen at 200°C was less than 5%. The photosensitive resin and its UV-cured specimen were also characterized by infrared (IR).

scholarly journals Curing Behavior, Rheological, and Thermal Properties of DGEBA Modified with Synthesized BPA/PEG Hyperbranched Epoxy after Their Photo-Initiated Cationic Polymerization

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2240
Author(s):  
Tossapol Boonlert-uthai ◽  
Kentaro Taki ◽  
Anongnat Somwangthanaroj
Keyword(s):  
Glass Transition ◽  
Thermal Properties ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Bisphenol A ◽  
Epoxy Resin ◽  
Cationic Polymerization ◽  
Gelation Time ◽  
Radius Of Gyration ◽  
Curing Behavior

This paper investigates the photo-initiated cationic polymerization of diglycidyl ether of bisphenol A (DGEBA) modified with bisphenol A (BPA)/polyethylene glycol (PEG) hyperbranched epoxy resin. The relationship between curing behavior, rheological, and thermal properties of the modified DGEBA is investigated using photo-differential scanning calorimetry (DSC) and photo-rheometer techniques. It is seen that the addition of the hyperbranched epoxy resin can increase UV conversion (αUV) and reduce gelation time (tgel). After photo-initiation polymerization (dark reaction) occurred, a second exothermic peak in the DSC thermogram takes place: namely, the occurrence of curing reaction owing to the activated monomer (AM) mechanism. Consequently, the glass transition temperature decreased, and at the same time, UV intensity increased which was due to the molecular weight between crosslinking points (Mc). Furthermore, the radius of gyration (Rg) of the network segment is determined via small-angle X-ray scattering (SAXS). It is noted that the higher the Mc, the larger the radius of gyration proves to be, resulting in low glass transition temperature.

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