Using dynamic mechanical analysis (DMA) we have studied thermal degradation for a system containing a diglycidyl ether of bisphenol A (DGEBA) and 1,3-bisaminomethylcylohexane (1,3-BAC). The changes of dynamic mechanical properties during thermal degradation indicated a shift of the glass transition temperature (Tg) to higher temperatures and a decrease in the peak value of the dynamic loss factor (tan δ) with an increasing of aging time. The value of dynamic storage modulus (E′) at the rubbery state showed an increase with aging time, whiteE′ at the glassy state only underwent a moderate change with increased thermal degradation. From these results it can be argued that thermal degradation during the stage prior to the onset of the severe degradation involves structural changes in the epoxy system, as further crosslinking and loss of dangling chains in the crosslinked network.

Dynamic mechanical analysis

https://ir.nctu.edu.tw:443/bitstream/11536/30406/1/000087123900011.pdf

Characterization and properties of new silicone-containing epoxy resin

3.1. Polysiloxane Macroinitiators 1239 3.1.1. Redox-Initiated Polymerization 1239 3.1.2. Photoinitiated Polymerization 1240 3.1.3. Ozonide Macroinitiators 1241 3.1.4. Bis-(silyl pinacolate) Macroinitiators 1241 3.1.5. Peroxycarbamate Macroinitiators 1241 3.1.6. Peroxyester Macroinitiators 1242 3.1.7. Azo Macroinitiators 1242 3.2. Polysiloxane Macromonomers 1245 3.2.1. Synthesis of Polysiloxane Macromonomers and Copolymerization 1245

Well-Architectured Poly(dimethylsiloxane)-Containing Copolymers Obtained by Radical Chemistry

The mechanisms of refractive index change in poly(methyl methacrylate) by frequency doubled femtosecond laser pulses are investigated. It is demonstrated that positive refractive index modificaton can be caused by a combination of depolymerization and crosslinking.

/pdf/mechanisms-of-femtosecond-laser-induced-refractive-index-44mvnwf09r.pdf

Mechanisms of femtosecond laser-induced refractive index modification of poly(methyl methacrylate)

Structured latex particles with a slightly crosslinked poly(styrene-n-butyl acrylate) (PSB) core and a poly(styrene–methacrylate–vinyl triethoxide silane) (PSMV) shell were prepared by seed emulsion polymerization, and the latex particle structures were investigated with Fourier transform infrared, thermogravimetric analysis, differential scanning calorimetry, transmission electron microscopy, and dynamic light scattering. The films that were formed from the structured core (PSB)–shell (PSMV) particles under ambient conditions had good water repellency and good tensile strength in comparison with films from structured core (PSB)–shell [poly(styrene–methyl methyacrylate)] latex particles; this was attributed to the self-crosslinking of CH2CHSi(OCH2CH3)3 in the outer shell structure. The relationship between the particle structure and the film properties was also investigated in this work. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1824–1830, 2006

Preparation and properties of core [poly(styrene‐n‐butyl acrylate)]–shell [poly(styrene–methyl methacrylate–vinyl triethoxide silane)] structured latex particles with self‐crosslinking characteristics

The thermal stabilities of various poly(alkyl methacrylate) homopolymers and poly(methyl methacrylate-g-dimethyl siloxane) (PMMA-g-PSX) graft copolymers have been determined by TGA As expected, the thermal stabilities of poly(alkyl methacrylates) were a function of the ester alkyl group, and polymerization mechanism In particular, thermally labile linkages, which result from termination during free radical or nonliving polymerization mechanisms, decrease the ultimate thermal stabilities of the polymers However, graft copolymers, which were prepared by the macromonomer technique with free radical initiators, exhibited enhanced thermal stability compared to homopolymer controls

S. D. Smith

Papers

Thermogravimetric analysis of poly(alkyl methacrylates) and poly(methylmethacrylate‐g‐dimethyl siloxane) graft copolymers