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As a multifunctional filler, carbon materials play an important role in enhancing the comprehensive properties of polypropylene composites. However, it is an important task to balance the relationship between the amount of different carbon materials and the formability and functionality of composite products. In this paper, the properties of carbon fiber, carbon nanotube and graphene, and the effects of these carbon materials on the mechanical, thermal and electrical properties of polypropylene-based multi-scale composites are discussed respectively. It is pointed out that it is a challenging research direction to prepare polypropylene composites filled with high content and hybrid carbon materials by melt deposition 3D printing process in the future. [ABSTRACT FROM AUTHOR]

A new kind of bio-based polyamide 5,6 (PA56) fiber has been synthesized from adipic acid and 1,5-pentanediamine. In this report, the characterization, antistatic treatment, mechanical properties, moisture absorption, mass-specific electrical resistance, and static electricity of the PA56 staple fibers were investigated. The spinnability of the PA56 yarns was studied. The results showed that the breaking strength of the PA56 fibers was 3.55 cN·dtex−1, the breaking elongation was 61.60% and the initial modulus was 49.32 cN·dtex−1. The PA56 staple fibers had an excellent moisture absorption of 4.68% and the easy release of water from the fibers. The release of water absorbed on the staple fibers made the carding processing of the PA56 fibers difficult due to electrostatic aggregation. Thus, an antistatic treatment of the PA56 staple fibers was carried out. Compared with the untreated fibers, the treated fibers exhibited a spectacular improvement in conductivity which led to their high efficiency of carding and good spinnability. The potential of the PA56 staple fibers carding web decreased from +21.2 to +0.04 kv when treated. The mass-specific electrical resistance of the treated PA56 staple fibers decreased from more than 104 MΩ·g·cm−2 to 290 MΩ·g·cm−2 both at a relative humidity (RH) of 35%, and from 1500 to 9.5 MΩ·g·cm−2 both at a 65% RH. The Ring yarn and Siro-spun yarn were successful produced by their spinning systems. The measurement results of the yarns demonstrated that the Siro-spun yarn had better properties than the Ring yarn, such as tensile strength, unevenness (CV%), hairiness index (H) and abrasion resistance. [ABSTRACT FROM AUTHOR]

Near-Infrared Spectroscopy (NIRS) is the most rapidly developing and the most noticeable spectrographic technique in the 80's (the last century). Its developing history and utilization in foreign countries were introduced. The authors mainly summarized the applications of NIRS to the field of forestry. The applications of near-infrared reflectance spectroscopy (NIRS) in fruit quality, timber and seed quality analysis are more active in forestry due to its rapid, timely, less expensive, non-destructive, straightforward analytic characteristics. In the last two decades, non-destructive methods using near-infrared spectroscopy (NIRS) to evaluate parameters for estimating maturity were applied to different fruits species to check the ripening status of fruits on trees or to grade fruits in the packing house, to assess fruit quality, such as sugar and acid contents, soluble solids, firmness of fruit, offers great advantages to growers in deciding when to harvest. The near infrared spectrophotometry (NIRS) can also be used the nondestructive quantitative assessment of the solid wood density, the moisture condition and the lignin content in bulky wood. The previous results indicated that the utility of NIRS was a selection tool in breeding programs, for example, three kids of persimmon fruits, astringent, non-astringent and half-astringent, were clearly classified by using Near-infrared (NIR) methods, and based on the combination of near infrared technology and multivariate analysis, the genetic, physiological and technical qualities of both temperate and tropical tree species on single seed basis can be characterized. It has already been shown that NIRS can predict the chemical composition of litters. NIRS is also capable of correlating the initial spectral characteristics of the litters with their short- and medium-term decomposability. The stage of decay of decomposing leaves can be predicted by using the near infrared reflectance spectroscopy. The method is rich in information and quick to conduct. However, the applications of NIRS to the field of forestry in our country are only on the beginning, and are mainly focused on wood characteristics and fruit quality testing. In fact, there are still some further applications of NIRS in forestry in future, such as analyzing trace elements in fruit, biosecurity inspection. In this paper, the authors analyzed the NIRS applications status in home and abroad, and discussed the applied prospects to promote its applications to the field of forestry research and practical programs in our country.