Preparation Of Fibers Research Articles

Solvent-free preparation of carbon fiber reinforced dynamically cross-linked vanillin-based polyurethane composites with excellent self-healing and closed-loop recycling performance

Disposing of the wastes generated from the carbon fiber reinforced polymer (CFRP) composite materials after service failure has attracted great attention in recent years. CFRP composites prepared with dynamically covalent cross-linking polymers as matrix resins possess excellent self-healing and recyclability performance, providing an efficient solution to overcome this challenge. However, most of the dynamic cross-linking resins are typically made by high-cost petroleum-derived compounds with extensive use of organic solvents and environmentally unfriendly catalysts. Herein, catalyst-free self-healing and recyclable vanillin-based polyurethanes (V-PUs) via dynamic phenol-carbamate bonds were synthesized by a one-step solvent-free method with a biodegradable PCL as soft segment and biobased vanillin derivative as the chain extender. The optimized V-PUs exhibit Young's modulus of 1.92 GPa, stress at break of 64.98 MPa, glass transition temperature of 95 °C, and over 90 % self-healing and reprocessing efficiency. This excellent self-healing and reprocessing performance can be successfully transferred to the CFRP composite materials fabricated with the V-PUs as matrix resins by hand paste-vacuum bag pressing method. The interlayer shear strength (ILSS) of the composite material is 41 MPa, and the healing efficiency determined by ILSS reaches 85.34 %. Closed-loop recovery of the carbon fiber and matrix resin from the CFRP composite is realized through the solvent dissolution approach due to the dynamic character of the phenol-carbamate bonds, which is of great significance for the development of green economy and sustainable society.

Study on the preparation and mechanical behavior of carbon fiber reinforced aluminum matrix composites stator blade

The advancement of high-performance stator blades stands as a critical avenue for enhancing the efficacy of aero engines. This study aims to prepare carbon fiber reinforced aluminum matrix (CF/Al) composite stator blades with high-quality shapes and properties, optimize the lay-up design using Fibersim software, and investigate the effect of extrusion temperature on the forming quality. The mechanical properties and damage behavior were systematically analyzed by tensile, compression, and interlaminar shear tests. In addition, the vibration mode simulation reveals the force state under the 1st to 8th-order vibration modes. Results indicate that the [0°/+45°/0°/-45°/90°/-45°/0°/+45°/0°] lay-up parameters were optimal, achieving excellent shape and performance of curved preforms after curing. Composite blades fabricated at an extrusion temperature of 680°C exhibited clear contours, consistent dimensions, and no macro defects. SEM and EDS analyses showed uniform impregnation in all regions of the blade, high density, and good densification. Compared with the matrix alloy, the tensile strength of the composite blade was improved by 64.94%, the compressive strength by 35.7%, and the interlayer shear strength was as low as 72.6 MPa. The vibration mode simulation verified the applicability of the blade in the first-order vibration mode, which provides strong support for the application of composite materials in the aerospace field.

Stable Persistent Room-Temperature Phosphorescent Hydrogels Based on Ionically Crosslinked Nonaromatic Carboxylate Polymers.

Developing pure organic room-temperature phosphorescent (RTP) hydrogels is important for expanding the practical applications of phosphorescent materials. However, most of the reported RTP hydrogels containing aromatic phosphors suffer from short phosphorescent lifetimes, unstable underwater RTP emissions, and complex preparation processes. Herein, novel nonaromatic RTP hydrogels are prepared by using two types of non-traditional luminescent polymers, sodium alginate and a polymeric carboxylate, which are not RTP emissive or very weakly emissive in aqueous environments. The prepared hydrogels exhibit the following features: I) color-tunable RTP emissions with ultra-long lifetimes up to 451.1ms, II) excellent anti-swelling properties and stable persistent RTP emission even after being immersed in deionized water for months, III) efficient and large-scale preparation of hydrogel fibers by wet spinning technique. Experiment results and theoretical calculations show that the stable and long-lifetime RTP emissions of the hydrogels originate from the introduction of more nonconventional chromophores which are strongly crosslinked with ionic bonding between carboxylate groups and calcium ions and enhanced through-space interactions between them. This work provides a reliable strategy for designing nonaromatic hydrogels with stable and persistent RTP.

Preparation and properties of Ta fiber reinforced high-entropy (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)B2-SiC composite ceramics

High-entropy boride ceramics are expected to be widely used in aerospace, automotive turbines, and armor protection due to their advantages of high melting point, high hardness, adjustable performance, high-temperature stability, and good oxidation resistance. However, it is urgent to solve the problem of low fracture toughness before application. Therefore, in this paper, a single-phase high-purity (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)B2 powder was prepared by boron/carbon thermal reduction method using a vacuum furnace. The effects of synthesis temperature and C content on the powder were studied. Secondly, HEB ((Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)B2) powder, SiC powder, and chopped Ta fiber were mixed uniformly, and Ta fiber toughened HEB-SiC composite ceramics were prepared by spark plasma sintering (SPS). The effects of Ta fiber content on the phase composition, microstructure, mechanical properties, and oxidation resistance of the composite ceramics were investigated. The results show that with the increase in synthesis temperature, the HEB powder gradually dissolves, and the solid solution is completely formed at 1700 °C. As the C content increases, the oxygen content and particle size of the powder gradually decrease. Single-phase high-entropy (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)B2 powders with high purity were prepared at 1700 °C for 1 h with 6 wt% C content. The addition of C will promote the boron/carbon thermal reduction method, reduce the oxygen content, and inhibit grain growth. With the increase of Ta fiber content, the density of HEB-SiC-Taf composite ceramics increased first and then decreased. The hardness gradually decreased, and the fracture toughness gradually increased. When the Ta fiber content was 7 vol%, the fracture toughness was the highest, reaching 5.12 ± 0.39MPa⋅m1/2, which was nearly 45 % higher than that of the composite ceramics without Ta fiber. This is because of the synergistic toughening mechanism of metal toughening and fiber toughening, such as crack deflection, crack bridging, fiber debonding, and fiber pullout, which improves the fracture toughness of the composite ceramics. With the increase in oxidation temperature, B2O3, SiO2, Ta2O5, and various metal oxides appear on the surface of HEB-SiC-Taf composite ceramics. The oxidation depth and weight gain per unit area gradually increase. When the Ta fiber content is 5 vol%, the composite ceramics exhibit the best high temperature stability and oxidation resistance. This is due to the Ta2O5 formed by the oxidation of Ta fibers, which dissolves into the B2O3 glass phase, increasing viscosity and improving high temperature stability while reducing the oxygen diffusion rate.

Numerical Study of Melt-Spinning Dynamic Parameters and Microstructure Development with Ongoing Crystallization.

In response to an investigation on the paths of changes in the crystallization and radial differences during the forming process of nascent fibers, in this study, we conducted numerical simulation and analyzed the changes in crystallization mechanical parameters and tensile properties through a fluid dynamics two-phase model. The model was based on the melt-spinning method focusing on melt spinning, the environment of POLYFLOW, and the method of joint simulation, coupled with Nakamura crystallization kinetics, including the development of process collaborative parameters, stretch-induced crystallization, viscoelasticity, filament cooling, gravity term, inertia, and air resistance. Finally, for nylon 6 BHS and CN9987 resin spinning, the model successfully predicted the distribution changes in temperature, velocity, strain rate tensor, birefringence, and stress tensor along the axial and radial fibers and obtained the variation pattern of fibers' crystallinity along the entire spinning process under different stretching rates. Furthermore, we also explored the effects of spinning conditions, including inlet flow rate, winding speeds, and the extrusion temperature, on the fibers' crystallization process and obtained the influence rules of different spinning conditions on fiber crystallization. Knowing the paths of changes in mechanical performance can provide important guidance and optimization strategies for the future industrial preparation of high-performance fibers.

Characterization of Fibers Prepared by Centrifugal Spinning from Biotechnologically Derived Chicken Gelatin.

The application of biopolymer-based materials is increasing due to better sustainability and environmental protection properties. Gelatin fibers have a specific surface and high porosity, which is why their use in medicine and the food industry is being researched. This article explores the potential of centrifugal spinning to produce gelatin fibers. Gelatin for fiber preparation was obtained from a non-traditional source of collagen (chicken by-products) using a unique enzymatic process. The fiber quality was compared with those prepared from gelatins produced from traditional collagen tissues (porcine, bovine). The results showed that fibers cross-linked with glutaraldehyde vapor preserved their structure even in contact with water. Using a cross-linker controlled swelling ability and solubility while maintaining the fiber structure. On the contrary, uncross-linked gelatin fibers were water soluble due to a high surface-to-volume ratio, facilitating water penetration and dissolution. Scanning electron microscopy (SEM) provided a clearer picture of the morphology of gelatin fibers obtained by centrifugal spinning. Differences in the amount of bonding depending on the raw material used and the presence of a cross-linker were analyzed using Fourier transform infrared spectroscopy (FTIR). The overall results showed that chicken gelatin is a suitable alternative to gelatins from traditional sources and can be used for preparing food and pharmaceutical packaging and coatings, fibers, or bioprinting of 3D matrices.

Preparation of cellulose-based porous carbon fibers and their methylene chloride adsorption/desorption behaviors

Methylene chloride is a type of volatile organic compounds for which effective and economical treatment and recovery technologies need to be developed because it is impossible to reburn. In this study, a cellulose-based porous carbon fibers were prepared for the adsorption/desorption of methylene chloride. From the results, the specific surface area and total pore volume of cellulose-based porous carbon fibers were determined to be 1700–2220 m2/g and 0.69–1.03 cm3/g, respectively, and the micropore ratio was observed to be high. As the activation time increased, methylene chloride activity and methylene chloride retentivity increased from 51.75 % to 58.07 % and from 9.08 % to 14.92 %, respectively. Methylene chloride adsorption/desorption showed a high correlation with pore volume, Especially, methylene chloride retentivity had a linear relationship between the mesopore volume and mesopore ratio.

Preparation of ultra-high permeability dual-layer Al2O3 hollow fiber supports for zeolite membrane fabrication

Four-channel dual-layer Al2O3 hollow fiber with ultra-high permeability and mechanical strength was prepared by co-extrusion and co-sintering technique for the first time and used as support for NaA zeolite membranes fabrication. The macroporous inner layer of the Al2O3 hollow fiber, composed by large Al2O3 particle, gives supports the high permeability and mechanical strength, while the thin out layer, composed by small particles, provides an even and smooth surface for zeolite membrane growth. By using SiO2 as the sintering aid, the sintering temperature of the inner layer was reduced and match with that of the outer layer. The effects of SiO2 adding amount, sintering temperature, Al2O3 particle size and their content on the structure and properties of the prepared hollow fiber were investigated systematically. At a sintering temperature of 1520 °C, a dual-layer hollow fiber with surface pore size of 0.38 μm and fracture load of 24.52 N, exhibits pure water flux as high as 22.23 m3 m 2 h−1 bar−1. The NaA membrane prepared on this support achieved a flux of 14.14 kg m−2 h−1 and a separation factor >10,000 in pervaporation separation of EtOH/H2O solution (90 wt%, 75 °C). This work provides an efficient and low-cost way to prepare ceramic hollow fiber support for high-performance zeolite membrane fabrication.

Preparation of water-soluble dietary fiber from bamboo shoots by fungi fermentation and its supplementation in biscuits

Expanding the utilization of bamboo shoots is extremely meaningful in China because of the high output every year. In this study, the bamboo shoot powder was used as a substrate to produce water-soluble dietary fiber (WSDF) by fermentation with a screened fungi strain Trichoderma dorotheae MLG23, and the prepared WSDF was utilized in the production of biscuits. The bamboo shoots and their residues, WSDF, and biscuits were analyzed on Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), inductively coupled plasma mass spectrometry (ICP-MS), and texture analyzer. The results showed that the fungi exhibited a strong ability to express extracellular cellulase. The enzymatic activities of filter paper activity (FPA), cellobiohydrolase (CBH), and ꞵ-glucosidase (BG) secreted by the strain showed the highest at 50 °C, reaching 0.13, 0.19, and 1.20 U/mL, respectively, and the highest enzymatic activity of endoglucanase (EG) with 0.37 U/mL was obtained at 60 °C. The highest WSDF yield of 45.97 wt% was obtained under the fermentation conditions of bamboo shoot loading 30 g/L, strain inoculum 1010 CFU/L, and fermentation time 4 d at 30 °C. The cellulose and hemicellulose in bamboo shoots were partially utilized by the fungi to produce WSDF. The main metal elements in WSDF were Mg, K, Ca, and Zn. The hardness, cohesion, chewiness, resilience, and adhesion of the biscuits showed a gradual decrease with the increase of WSDF addition in the range from 0 to 10 g per 100 g of low gluten flour. The incorporation of WSDF disrupted the network structure of the gluten, leading to the reduction of some textural properties and the change of microstructure. These results showed a potential utilization of bamboo shoot in production of WSDF and functional biscuits.

Harmonization of experimental procedures to assess mitochondrial respiration in human permeabilized skeletal muscle fibers

AimHigh-resolution respirometry in human permeabilized muscle fibers is extensively used for analysis of mitochondrial adaptions to nutrition and exercise interventions, and is linked to athletic performance. However, the lack of standardization of experimental conditions limits quantitative inter- and intra-laboratory comparisons. MethodsIn our study, an international team of investigators measured mitochondrial respiration of permeabilized muscle fibers obtained from three biopsies (vastus lateralis) from the same healthy volunteer to avoid inter-individual variability. High-resolution respirometry assays were performed together at the same laboratory to assess whether the heterogenity in published results are due to the effects of respiration media (MiR05 versus Z) with or without the myosin inhibitor blebbistatin at low- and high-oxygen regimes. ResultsOur findings reveal significant differences between respiration media for OXPHOS and ETcapacities supported by NADH&succinate-linked substrates at different oxygen concentrations. Respiratory capacities were approximately 1.5-fold higher in MiR05 at high-oxygen regimes compared to medium Z near air saturation. The presence or absence of blebbistatin in human permeabilized muscle fiber preparations was without effect on oxygen flux. ConclusionOur study constitutes a basis to harmonize and establish optimum experimental conditions for respirometric studies of permeabilized human skeletal muscle fibers to improve reproducibility.

The feasibility and rationale for utilizing high molecular weight PBT in the preparation of high-strength fiber

Polyethylene terephthalate (PET) industrial yarn is prone to damage during weaving due to its insufficient flexibility. Therefore, it is worth exploring whether polybutylene terephthalate (PBT) with improved flexibility can be utilized for the production of high strength and low modulus industrial yarn. In this study, a low velocity spinning multi-stage multi-ratio drawing technology route was employed for spinning, but PBT fibers only achieved a break strength of 5.1cN/dtex, which was lower than that of PET fibers (7.2cN/dtex). By comparing the multi-level structure evolution of PET and PBT during spinning, it was found that the core problem limiting the strength improvement of PBT fibers is due to the early formation of folded chain lamellar structure in PBT as-spun fibers during cooling, which hinders conformational transition during hot drawing and limits the drawing ratio. This has important implications for the development of PBT industrial yarn technology by adjusting the crystallization characteristics of PBT as-spun fibers.

Experimental Study on Preparation of Inorganic Fibers from Circulating Fluidized Bed Boilers Ash.

The ash generated by Circulating Fluidized Bed (CFB) boilers is featured by its looseness and porosity, low content of glassy substances, and high contents of calcium (Ca) and sulfur (S), thus resulting in a low comprehensive utilization rate. Currently, the predominant treatment approach for CFB ash and slag is stacking, which may give rise to issues like environmental pollution. In this paper, CFB ash (with a CaO content of 7.64% and an SO3 content of 1.77%) was used as the main raw material. The high-temperature melting characteristics, viscosity-temperature characteristics, and initial crystallization temperature of samples with different acidity coefficients were investigated. The final drawing temperature range of the samples was determined, and mechanical property tests were conducted on the prepared inorganic fibers. The results show that the addition of dolomite powder has a significant reducing effect on the complete liquid phase temperature. The final drawing temperatures of the samples with different acidity coefficients range as follows: 1270-1318 °C; 1272-1351 °C; 1250-1372 °C; 1280-1380 °C; 1300-1382 °C; and 1310-1384 °C. The drawing temperature of this system is slightly lower than that of basalt fibers. Based on the test results of the mechanical properties of inorganic fibers, the Young's modulus of the inorganic fibers prepared through the experiment lies between 55 GPa and 74 GPa, which basically meets the performance requirements of inorganic fibers. Consequently, the method of preparing inorganic fibers by using CFB ash and dolomite powder is entirely feasible.

Preparation and characterization of silica sol-impregnated glass fibers

Abstract Silica sol-impregnated glass fiber products were prepared via the sol-gel method, with tetraethoxysilane (TEOS) as a precursor and hydrochloric acid (HCl) as a catalyst, and characterized by 1H NMR, FT-IR, and solid 29Si NMR analyses. The results indicated that the structure of the impregnating agents was significantly affected by the amount of water added. With a decrease in the molar ratio of added water, the degree of TEOS hydrolysis was reduced, and more ethoxy groups -OCH2CH3 were formed, resulting in the formation of sol products with a linear structure. Furthermore, contact angle and water absorption tests showed that as the molar ratio of water increased, the water contact angle decreased, whereas the water absorption of impregnated glass fiber increased. These results indicate that a higher hydrolysis degree of TEOS with more added water generates more Si-OH groups, facilitating the cross-linking of sol products to form a network structure.

Mechanically Robust Biopolymer Optical Fibers with Enhanced Performance in the Near-Infrared Region.

Polymer optical fibers (POFs) are lightweight, fatigue-tolerant, and suitable for local area networks, automobiles, aerospace, smart textiles, supercomputers, and servers. However, commercially available POFs are exclusively fabricated using synthetic polymers derived from nonrenewable resources. Recently, attempts have been made to fabricate biocompatible and biopolymeric optical fibers. However, their limitations in mechanical performance, thermal stability, and optical properties foil practical applications in waveguiding. Here, we report a comprehensive study of the preparation of biopolymer optical fibers with tailored mechanical strength, thermal properties, and their short-distance applications. Specifically, we use alginate as one of the key components with methylcelluloses to promote readily scalable wet spinning at ambient conditions to fabricate 21 combinations of composite fibers. The fibers display high maximum strain (up to 58%), Young's modulus (up to 11 GPa), modulus of toughness (up to 63 MJ/m3), and a high strength (up to 195 MPa), depending on the composition and fabrication conditions. The modulus of toughness is comparable to that of glass optical fibers, while the maximum strain is nearly 15 times higher. The mechanically robust fibers with high thermal stability allow rapid humidity, touch sensing, and complex shapes such as serpentine, coil, or twisted structures without losing their light transmission properties. More importantly, the fibers display enhanced optical performance and sensitivity in the near-infrared (NIR) region, making them suitable for advanced biomedical applications. Our work suggests that biobased materials offer innovative solutions to create short-distance optical fibers from fossil fuel-free resources with novel functionalities.

Cellulose-based aerogels, films, and fibers for advanced biomedical applications

Cellulose possesses hydrophilicity, high water retention capacity, excellent mechanical properties, and biocompatibility, making it a promising candidate material for biomedical applications. As a substrate and dispersant used in the preparation of aerogels, films, and fibers, it improves their moisturizing ability, water absorption, drug utilization and slows down the rate of drug release, demonstrating outstanding therapeutic effects in biomedical research. This review summarizes and discusses the latest advancements in the application of cellulose-based aerogels, films, and fibers in the biomedical field. First, the properties of cellulose and its application principles in biomedical materials are analyzed. Second, the methods for preparing cellulose-based aerogels, films, and fibers are summarized, along with their advantages and disadvantages. Then, the latest research progress of cellulose-based aerogels, films, and fibers in drug delivery, wound dressings, and tissue engineering scaffolds is reviewed. Finally, the review concludes with a summary and provides future development directions for the field.

Investigation of Tensile and Impact Properties of Pineapple Leaf Fiber-Glass Fiber Reinforced Polymer (GFRP) Hybrid Composites

Kontes Kapal Cepat Tak Berawak Nasional (KKCTBN) held by Pusat Prestasi Nasional (Puspresnas) Kemendikbudristek RI aims to encourage innovation in the design and performance of shipping-maritime technology prototypes. The selection of the right material for the catamaran hull is very important because it affects the strength and weight of the ship. Materials such as fiber reinforced polymer, which uses glass fiber, are often used due to their good mechanical strength. However, natural fibers such as pineapple leaf fiber also have potential as composite reinforcement. The combination of natural and synthetic fibers, such as pineapple leaf fiber and glass fiber, in hybrid composites can improve the mechanical properties of the material. The purpose of this study was to investigate tensile and impact properties of pineapple leaf fiber-glass fiber reinforced polymer (GFRP) hybrid composites. Fiber preparation was carried out by separating pineapple leaf to produce fibers, alkaline treatment using 10% NaOH with a soaking time of 24 hours, and oven drying at 100?C for 60 minutes. Polymer as the matrix used was 50% while the percentage variations of pineapple leaf fiber and glass fiber were sequentially as follows 5%:45%, 10%:40% and 15%:35%. It was found that the tensile strength of the 10% pineapple leaf fiber composite was about 114 MPa and impact strength 49.96 J/mm², density 1.19 g/cm3. The results of this study indicate that the resulting composite can be used as an alternative material in the prototype hull of a catamaran type unmanned speedboat.

Preparation and characterization of ox bone powder and bamboo fibers reinforced hybrid epoxy composites

Composite materials are one of the fastest growing when compared with metal, ceramic, and polymer due to their high specific strength, stiffness, and versatile application in various fields. This study aimed to develop an ox bone powder and bamboo fiber-reinforced hybrid epoxy composite for stock and bumper applications and investigate the effect of the reinforcements on the composite’s mechanical properties. The reinforcements used in this work were random orientations of animal bone (ox) powder of 75 microns and bamboo fiber. The matrix used for this work was epoxy resin. Composite materials were prepared using the hand layup method with a 40% weight fraction of reinforcement (bone powder and bamboo fiber) and a 60% weight fraction of epoxy resin matrix. Five different combinations of bone powder and bamboo fiber with a fixed amount of epoxy resin were used for this work. The combinations of bamboo fiber and bone powder were: 40% bamboo fiber with 0% bone powder; 30% bamboo fiber with 10% bone powder; 20% bamboo fiber with 20% bone powder; and 0% bamboo fiber with 40% bone powder. The mechanical properties studied were compressive strength, impact strength, and flexural strength. In addition, water absorption was studied for all combinations. The maximum results of the flexural and impact strengths were 278.91 MPa and 7.5 J/m, respectively, at a 0:40 (bone powder: bamboo fiber) composite. The maximum compressive strength and the lowest absorption obtained were 283.3 MPa and 1.05%, respectively, at the 40:0 (bone powder: bamboo fiber) composite. For the hybrid composite case, optimal flexural and impact strengths were 236.72 MPa and 6.66 J/m, respectively, and water absorption was 1.52% at 10:30 (bone powder: bamboo fiber). Since reasonable flexural strength, impact strength, and water absorption were obtained with the hybrid composite of 10:30 (bone powder: bamboo fiber), this combination of the hybrid composite is recommended for stock and bumper applications.

Preparation and properties of phosphorus-containing thermotropic liquid crystal copolyester fibers with excellent flame retardance and mechanical property

In order to acquire polymeric fibers have both excellent flame retardance and mechanical properties, high molecular weight phosphorus-containing liquid crystal copolyesters derived from 6-hydroxy-2-naphthenic acid (HNA), terephthalic acid (TA) and 10-(2,5-dihydroxypheny)-10-hydro-9-oxa-10-phospha phenanthrene-10-oxide (DOPO-HQ) were synthesized via “one-pot” melt polymerization, and then the fibers were obtained by melt spinning method. The structure and property of the copolyesters were studied elaborately by experimental characterization technique and molecular simulation method. Shear shinning behavior was observed from rheology measurement, indicating that the copolyesters had excellent melt fluidity and spinnability. The rigidity of molecular chain was efficiently improved by the phosphorus-containing monomer DOPO-HQ and naphthalene HNA units which could be reflected by the molecular simulation results as well as high Tg values. The flame retardant mechanism of the phosphorus-containing flame retardant copolyester was systematically studied via limiting oxygen index (LOI), vertical burning (UL-94) test, cone calorimetry, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results showed that the copolyesters exhibit synergistic flame retardant mechanism of gas phase and condensed phase. Meanwhile, mechanical property of the as-spun fibers could be significantly improved by increasing the spinneret draw ratio (SDR) attributed to high molecular chain orientation. The maximum tensile strength of the as-spun fiber was 0.77 GPa observed for P-HNA60P20 at a relatively low SDR of 29. It was shown the unique combination of good thermal stability, spinnability as well as mechanical and flame retardant properties of the copolyesters would make them could be used as high-performance flame retardant materials.

Impact of Malting and Moist-steaming on Carbohydrate and Dietary Fibre Quotient of Millets and its Utilization in the Preparation of Low Estimated Glycemic Index and High Fibre Pizza Base

Background: The Carbohydrate and dietary fibre quotients (CQ and DFQ) are an indication of total carbohydrate, dietary fibre and its fractions viz. soluble and insoluble. Malting is a nutrition transition natural method having many benefits. Further, a resistant starch (RS) is called a fraction of dietary fibre which forms on heating starch rich foods. Millets were malted and moist steamed in order to improve CQ and DFQ and used in preparation of pizza base. Methods: The moist steamed millets (MSM) malt was analyzed under Scanned Electronic Microscopic (SEM) to detect RS. The developed pizza base was analyzed for proximate composition, in-vitro digestibility and Estimated Glycemic Index (EGI) etc. Result: The SEM of moist steamed malt showed the retrograded starch molecules as an effect of moist steaming and cooling process. The proximate composition of pizza base showed a significant change in all parameter on fortification. The microbial parameters were slightly affected on fortification. The total starch, rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS) content were too reduced on fortification. The Hydrolysis Index (HI) and Estimated Glycemic Index (EGI) were too decreased from 45.06 to 31.74 and 64.45 to 53.14 respectively on fortification. Hence, it is concluded that the MSM malt utilization in pizza base has impact on overall quality of pizza base including physico-chemical properties, microbial and EGI. The high fibre and RS millets malt could be utilized in the preparation of high fibre and low EGI pizza base.

Preparation of short carbon fiber reinforced photosensitive resin and composite material properties study

AbstractLight‐curing rapid prototyping (SLA) has become an emerging technology in the manufacturing industry because of its high precision, rapid prototyping, and the ability to mold complex parts. To enhance the mechanical properties and thermal stability of its raw material photosensitive resin (PR), carbon fiber (CF) was surface modified by chemical oxidation and grafting of amino silane (KH550) to obtain KH550‐modified carbon fiber (ACF). Then, ACF was composited with photosensitive resin to obtain modified carbon fiber/photosensitive resin (ACF/PR) composites. The viscosities of ACF/PR composites, including the viscosity, curing shrinkage, mechanical properties, and thermal stability of the ACF/PR composites, were characterized. The results showed that KH550 was successfully grafted onto CF. When the addition of ACF in the composites was 0.6%, the tensile strength, elongation at break, and impact strength of ACF/PR reached 39.48 MPa, 20.32%, and 13.62 kJ/m2, which were 120%, 27.15%, and 154% higher than that of the pure resin; the thermal decomposition temperatures and the maximum thermal decomposition temperatures at 50% mass loss of ACF/PR increased to 457.66°C and 442.44°C at 50% mass loss, which is 3.95% and 3.63% higher than that of the pure resin. Currently, the composites have excellent strength, toughness, and thermal stability. This paper gives a cost‐efficient method for improving the functioning of PR.Highlights Mixed acid oxidation and amino silane modification of CFs. Preparation of modified CF/photosensitive resin composites. Composites with excellent mechanical properties and thermal stability.