Comparison between the preparation,structure and mechanical properties of long fiber reinforced thermoplastics and short fiber reinforced thermoplastic

This article summarizes the comparison between the preparation, structure and mechanical properties of long fiber reinforced thermoplastics （LFT） and short fiber reinforced thermoplastics （SFT）. Both of the experiment and theory results showed that the mechanical properties of long glass fiber reinforced thermoplastics pellets （LGFRT） have been enhanced better than that of short glass fiber reinforced thermoplastics pellets （SGFRT） manufactured by molding procession. After regulation of the relative humidity by 50 % , the mechanical properties of 30 % （ weight percent） short glass fiber content in SFT （ SFT-PA6-SGF30 ） are similar to that of 40 % long glass fiber content in LFT. Howev- er, the density of the latter is about 17 % lower than that of the former. Thus, the corresponding weight of products is reduced by 13 % ;output rate is increased by 21% , and the cost is therefore significantly lowered. And it has the fol- lowing advantages： impact strength is increased by 87 % ; the proportion is reduced by 20 % ; molding cycle is short- ened by 10 % ;materials cost is saved by 20 % -30 % and the final total cost is saved by 30 % -40 %. So LFT （LFT-PP-LGF40） can replace SFT （SFT-PA6-SGF30） with the similar basic mechanical properties under normal tem- perature or 160 ℃ lower.

Pushing the limits of microwave absorption capability of carbon fiber in fabric design based on genetic algorithm

The field of electromagnetic wave absorption(EWA)requires the adaptability,tenability,and multifunction of high-performance materials in the future.The design and preparation of EWA materials aiming at performance requirements is the latest research hotspot.Here,a performancedriven strategy for simultaneously coordinating different target performances was proposed to optimize the structure of the periodical long continuous carbon/glass fiber fabric(PCGF)materials through algorithm and simulation.The optimized structure of the PCGF not only improves the impedance matching,but also introduces the induced orientation effect for a high cooperative loss of conductivity,resonance,and periodic structure.The flexible PCGF shows a broad effective absorption bandwidth(EAB)of 32.7 GHz covering a part of the C-band and the whole X-,Ku-,K-,and Ka-bands with a thickness(d)of only 0.92 mm and a density of 5.6×10^(−4) kg·cm^(−3).This highly designable fabric is promising for the EWA practical application owing to integrating the characteristics of good flexibility,acid and alkali resistance,bending resistance,excellent mechanical properties,and easy large-scale preparation.