In-Situ Phase Separation of an Amine-Terminated Siloxane in Epoxy Matrices

ABSTRACTWe have developed an amino-functional silicone resin to toughen epoxies which, when prereacted with the epoxy function in resins, undergoes in-situ phase separation during final epoxy curing. SEM analyses of the morphology of fracture surfaces of MY720- DDS, Epon 828-DDS and other epoxy matrices modified with the silicone resin showed rough surfaces with the formation of very uniform <10 μm spheres. Silicon and sulfur elemental distribution mapping showed silicon rich spheres embedded in an epoxy matrix. We report cavitation, particle debonding and pull-out, and an increases in fracture surface area as possible modes of toughening. Silicone modified materials give improvements in slow strain rate G1c fracture toughness measurements of 250–400%, similar to carboxy terminated polybutadiene-acrylonitrile copolymer (CTBN) modifiers, but with a much smaller flexural modulus loss. The Tg of the modified epoxy matrices are maintained, moisture resistance is improved, and flammability is reduced.

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Mechanical and Morphological Properties of Bio-Phenolic/Epoxy Polymer Blends

Molecules ◽

10.3390/molecules26040773 ◽

2021 ◽

Vol 26 (4) ◽

pp. 773

Author(s):

Ahmad Safwan Ismail ◽

Mohammad Jawaid ◽

Norul Hisham Hamid ◽

Ridwan Yahaya ◽

Azman Hassan

Keyword(s):

Mechanical Properties ◽

Phase Separation ◽

Polymer Blends ◽

Epoxy Polymer ◽

Flexural Modulus ◽

Polymeric Materials ◽

Morphological Properties ◽

Comparison Results ◽

Unique Material ◽

Different Types

Polymer blends is a well-established and suitable method to produced new polymeric materials as compared to synthesis of a new polymer. The combination of two different types of polymers will produce a new and unique material, which has the attribute of both polymers. The aim of this work is to analyze mechanical and morphological properties of bio-phenolic/epoxy polymer blends to find the best formulation for future study. Bio-phenolic/epoxy polymer blends were fabricated using the hand lay-up method at different loading of bio-phenolic (5 wt%, 10 wt%, 15 wt%, 20 wt%, and 25 wt%) in the epoxy matrix whereas neat bio-phenolic and epoxy samples were also fabricated for comparison. Results indicated that mechanical properties were improved for bio-phenolic/epoxy polymer blends compared to neat epoxy and phenolic. In addition, there is no sign of phase separation in polymer blends. The highest tensile, flexural, and impact strength was shown by P-20(biophenolic-20 wt% and Epoxy-80 wt%) whereas P-25 (biophenolic-25 wt% and Epoxy-75 wt%) has the highest tensile and flexural modulus. Based on the finding, it is concluded that P-20 shows better overall mechanical properties among the polymer blends. Based on this finding, the bio-phenolic/epoxy blend with 20 wt% will be used for further study on flax-reinforced bio-phenolic/epoxy polymer blends.

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In situ microscopic studies on the structures and phase behaviors of SF/PEG films using solid-state NMR and Raman imaging

Physical Chemistry Chemical Physics ◽

10.1039/c6cp03314h ◽

2016 ◽

Vol 18 (24) ◽

pp. 16353-16360 ◽

Cited By ~ 7

Author(s):

Congheng Chen ◽

Ting Yao ◽

Sidong Tu ◽

Weijie Xu ◽

Yi Han ◽

...

Keyword(s):

Phase Separation ◽

Solid State Nmr ◽

Random Coil ◽

Rich Domain ◽

Microscopic Studies ◽

Helix Conformation ◽

Phase Behaviors ◽

Protein Rich ◽

Β Sheet

SF was incompatible with PEG in some extent, and the phase separation took place in their blend film. The conformation of SF in the interface between SF and PEG was changed to the β-sheet, while that in the protein-rich domain remained in the random coil and/or helix conformation.

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Rubber-modified epoxies: In situ detection of the phase separation by differential scanning calorimetry

Polymer ◽

10.1016/0032-3861(93)90528-i ◽

1993 ◽

Vol 34 (18) ◽

pp. 3960-3961 ◽

Cited By ~ 6

Author(s):

Dong Pu Fang ◽

C.C. Riccardi ◽

R.J.J. Williams

Keyword(s):

Differential Scanning Calorimetry ◽

Phase Separation ◽

Scanning Calorimetry ◽

In Situ Detection

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Structure of Microphase-Separated Silica/Siloxane Molecular Composites

MRS Proceedings ◽

10.1557/proc-171-57 ◽

1989 ◽

Vol 171 ◽

Cited By ~ 8

Author(s):

Dale W. Schaefer ◽

James E. Mark ◽

David Mccarthy ◽

Li Jian ◽

C. -C. Sun ◽

...

Keyword(s):

Phase Separation ◽

Kinetic Studies ◽

Organic Content ◽

Small Particles ◽

X Ray ◽

Filled Elastomers ◽

Polymeric Networks ◽

Large Particles ◽

Molecular Composites

ABSTRACTThe structure of several classes of silica/siloxane molecular composites is investigated using small-angle x-ray and neutron scattering. These filled elastomers can be prepared through different synthethic protocols leading to a range of fillers including particulates with both rough and smooth surfaces, particulates with dispersed interfaces, and polymeric networks. We also find examples of bicontinuous filler phases that we attribute to phase separation via spinodal decomposition. In-situ kinetic studies of particulate fillers show that the precipitate does not develop by conventional nucleation-and-growth. We see no evidence of growth by ripening whereby large particles grow by consumption of small particles. Rather, there appears to be a limiting size set by the elastomer network itself. Phase separation develops by continuous nucleation of particles and subsequent growth to the limiting size. We also briefly report studies of polymer-toughened glasses. In this case, we find no obvious correlation between organic content and structure.

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