Influence of adding Mesocarbon Microbeads into C/C composites on microstructure and properties during carbonization

Abstract

This work tests the effect on microstructure, flexural strength, flexural moduli, plus the electrical and thermal conductivity of carbon/carbon composites with Mesocarbon Microbeads (MCMBs) content ranging 0 -30% by weight during carbonization. These composites were reinforced by oxidative PAN Base fiber felts, and matrix precursor was resol-type-phenolic resin. MCMBs with a weight fraction of 0 -30% were added to the matrix to elucidate the effect. Liquid-phase impregnation was applied to reinforce matrix carbon. Cured composites were stabilized at 230°C, then heat-treated at 400, 600, 800, 900 and 1000°C for carbonization. The measured flexural strength after heattreated at 1000°C was 51.20, 49.59, 43.55, and 38.76 MPa for MCMBs with 0, 10, 20, and 30% added to composites; mean flexural moduli were l.73, 1.24, 0.73, and 0.57 MPa, respectively. Adding MCMBs reduced both strength and modulus because of cracks and avoids caused by different shrinkage between resin and MCMBs; adding 30 wt % MCMBs raised thermal conductivity of C/C composites from 1.55 to 1.78 W/mK and reduced electric resistivity from 1.8 ϫ 10 Ϫ2 to 5.97 ϫ 10 Ϫ3 ⍀ cm.

Structure and mechanical properties of fluorine-containing glycidyl azide polymer-based energetic binders

“…This may be attributable to the flexibility of main chains of FGAP being improved via copolymerization resulting in a better intermolecular reaction and mechanical behaviors of polymeric binders. 40,41 Therefore, it is suggested that the synthesis of a flexible structural FGAP in the binder wileyonlinelibrary.com/journal/pi formulation of solid propellants can be one of the most promising solutions for overcoming the poor mechanical properties of GAP-based solid propellants.…”

Synthesis of Chiral Oligomer‐Grafted Biodegradable Polyurethanes and Their Chiral‐Dependent Influence on Bone Marrow Stem Cell Behaviors

“…The biodegradable polyurethane (PPFU/HDI: 1.6 + Lys-OMe, M n : 29.2 kDa, M w : 83.8 kDa) used in this experiment was synthesized by our laboratory. [ 26,27 ] N -acryloyl-L -valine, N -acryloyl-D -valine, methyl 2-(butylthiocarbonothioylthio)propanoate (RAFT agent, MCEBTTC), and mercapto-functionalized poly( N -acryloyl-L ( D )valine) ( L ( D )-PAV-SH, M w : 1.8 kDa, Figure S1, Supporting Information) were synthesized according to the procedures described in the Supporting Information. The water used in all experiments was purifi ed via a Millipore Milli-Q purifi cation system and had a resistivity higher than 18.2 MΩ cm −1 .…”

“…[ 26 ] Compared to other types of degradable materials such as poly(lactic acid), poly(lactic-co -glycolic acid) and poly( εcaprolactone), the PPFUs possess various advantages, such as good mechanical properties, easy modifi cation, and low toxicity of the degradation products. [ 27 ] The electron defi cient double bonds on the PPFUs backbone offer the unique advantage of modifi cation by methods such as Michael addition. [ 28 ] Here, the chiral monomer N -acryloyl-L ( D )-valine ( L ( D )-AV) was synthesized and polymerized to obtain the chiral oligomer, poly( N -acryloyl-L ( D )-valine) ( L ( D )-PAV), by reversible addition-fragmentation chain transfer polymerization (RAFT).…”

Network regulation and properties optimization of glycidyl azide polymer‐based materials as a candidate of solid propellant binder via alternating the functionality of propargyl‐terminated polyether

“…In this case, the compounds with an alkyne polyfunctionality have been used for the curing of GAP-based binder and included many kinds of alkyne-containing small molecules and alkyne-terminated polymers. Furthermore, depending upon the molecular-level structural characteristics, the small molecules of bis-propargyl-succinate (PBS), 15 dimethyl 2,2-di(prop-2-ynyl)malonate (DDPM), 25 1,4-bis(1-hydroxypropargyl)benzene (BHPB), 26 bis(propargyl ether) (BABE) 27 , bispropargylhydroquinone (BPHQ) 28 and so on, showed crucial impacts on the triazole network structure and mechanical performances of the GAP-based binder systems. The GAP-based binder cured with higher-alkyne-functionality molecules exhibited a higher modulus and strength.…”