Preparation and flammability properties of hybrid materials containing phosphorous compounds via sol-gel process

Organic-inorganic hybrid coatings containing phosphoric acid (PA) bonded to the organic-inorganic network were prepared from tetraethoxysilane (TEOS) using a sol-gel process. The effect of sol-gel phosphate-based flame retardant coating on polyacrylonitrile fabric properties (flammability, stiffness, and strength) was investigated. Sample characterization of the coated samples were investigated using differential thermal/thermogravimetric analysis (DTA/TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), and scanning electron microscopy (SEM). The results showed that hybrid coating on the polyacrylonitrile fabrics influenced fabric stiffness, strength, and flammability. And also, flammability of the coated samples after washing cycles was investigated, and the flame retardancy properties of the samples after 10 repeated washings were not completely lost.     

Preparation and characterization of modified collagen/PAN blending fibers

Graft modification of collagen with acrylonitrile in concentrated aqueous solution of sodium thiocyanate (NaSCN) is developed in this paper. This modification can largely change it’s solubility in water and can be applied in fiber production. Grafting modified collagen is characterized by infrared spectrum and wide angle X-ray diffraction. Wet spinning of PAN fibers containing several content of modified collagen is performed. The tests about these fibers show that breaking strength and sonic orientation decrease as the amount of collagen is raised. The addition of collagen can largely improve the moisture regain of PAN fiber. Micro-appearance of fibers observed under scanning electron microscope (SEM) presents circular cross section and longitudinal grooves on surface, the depth of grooves increases with the increasing draw ratio.     

Preparation of electrospun silk fibroin/Cellulose Acetate blend nanofibers and their applications to heavy metal ions adsorption

Silk fibroin (SF)/Cellulose Acetate (CA) blend nanofibrous membranes were prepared by electrospinning and their heavy metal absorbabilities were examined in an aqueous solution after ethanol treatment. The electrospun nanofibrous membranes were comprised of randomly oriented ultrafine fibers of 100–600 nm diameters. As a result of field emission electron microscope (FEEM), the anti-felting properties of the blend nanofibrous membranes were markedly improved after treatment with 100 % ethanol when SF was blended with CA. Metal ion adsorption test was performed with Cu²⁺ as a model heavy metal ion in a stock solution. The SF/CA blend nanofiber membranes showed higher affinity for Cu²⁺ in an aqueous solution than pure SF and pure CA nanofiber membranes. Especially, the blend nanofibrous membranes with 20 % content of CA had an exceptional performance for the adsorption of Cu²⁺, and the maximum milligrams per gram of Cu²⁺ adsorbed reached 22.8 mg/g. This indicated that SF and CA had synergetic effect. Furthermore, the parameters affecting the metal ions adsorption, such as running time and initial concentration of Cu²⁺, had been investigated. The results showed that the adsorption of the Cu²⁺ sharply increased during the first 60 min, the amount of metal ions adsorbed increased rapidly as the initial concentration increased and then slope of the increase decreased as the concentration further increased. This study provides the relatively comprehensive data for the SF/CA blend nanofibrous membranes application to the removal of heavy metal ion in wastewater.     

Study on morphological, rheological and physico/mechanical behavior of SEBS/CaCO3 nanocomposite

This work focuses on the modification of the mechanical properties and morphology, cure behavior and other characterization of nano CaCO₃ filled SEBS (Styrene-ethylene-butadiene-styrene) elastomers. The tensile strength was increased and compression set characterization was decreased with increasing content of nCaCO₃ value. The influence of the interfacial area and the volume fraction of filler were studied. Furthermore, isothermal cure characterization of neat and filled systems was performed using a torque rheometer. The most important finding base on the rheological studies was the catalytic effect of nCaCO₃ on cure reaction of SEBS, leading to the shorter curing time. Moreover, the kinetic analyses of rheograms revealed a marked decrease in the activation energy of the cure process upon raising nCaCO₃ content. Interestingly, MFI, Hardness, Tensile, Compression set testes showed that the hardness and tensile properties were dramatically increased and MFI and elongation decreased by the addition of nano CaCO₃ into SEBS system compared to pure blend resin. It was shown that the relative increase in tensile yield stress when increasing amount of interfacial agent was added, both depends on the volume of filler and the interfacial area. The nanoparticles shape, size and dispersion state were investigate through X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) method.     

Si-Al hybrid effect of waterborne polyurethane hybrid sizing agent for carbon fiber/PA6 composites

The interface of fiber-reinforced composites has remained a vexing problem that limits the use of the excellent properties of carbon fiber (CF) in composite applications. In the present study, waterborne polyurethane (WPU) hybrid sizing agents were prepared to improve the performances of CFs and the interface strength of CF/PA6 composites. The structural and mechanical properties of the single-CF and CF/PA6 composites were systematic investigated. The results showed that the mechanical properties of the CF/PA6 composites were significantly improved by adding of WPU hybrid sizing agent. The tensile and flexural strengths of the WPU/SiO₂/Al₂O₃ hybrid sizing agent treated CF/PA6 composites were increased by 24.0 % and 25.7 % than those of no-sizing treated CF/PA6 composites, respectively.     

Functional processing of PET fabrics using boehmite/silica/thiazole dye hybrid materials

A series of hybrid materials composed of boehmite/silica/thiazole dyes and prepared via the sol-gel process is synthesized from aluminum isopropoxide (AIP) and tetraethoxysilane using heteroaryl 2-amino-thiazole azo dyes. Heterocyclic 2-amino-thiazole azo dyes undergo a hydrolysis-condensation reaction with an appropriate proportion of AIP under a catalyst, at a constant ratio of vinyltriethoxysilane (VTES) and tetraethoxysilane (TEOS). The structures of these hybrid materials composed of boehmite/silica/thiazole dyes are characterized using Fourier transform infrared (FT-IR) analysis. The surface morphology of polyethylene terephthalate (PET) fabrics is evaluated using scanning electron microscopy (SEM). SEM images show uniform dyeing of the PET fabrics that confirms the reaction of the hybrid materials with the PET fabrics. The water contact angle, washing fastness, color evenness, air permeability, and warmth retention of the PET fabrics dyed with hybrid materials composed of boehmite/silica/thiazole dyes are evaluated. The evaluation results indicate improved warmth retention property and good water repellency.     

Preparation and property of ultrahigh molecular weight polyethylene/halloysite nanotube fiber

In this research, halloysite nanotubes (HNTs) were incorporated into ultra-high molecular weight polyethylene (UHMWPE) in order to prepare the nanocomposite fibers by a gel-spun and hot drawing process. The HNTs were treated with oleic acid to improve the dispersion in the UHMWPE fibers. Both the crystallinity tested by differential scanning calorimetry (DSC) and mechanical properties increased with a low loading of HNTs, and decreased with a high loading. The thermal gravimetric analysis (TGA) test showed the thermal stability to improve with the incorporation of HNT. The addition of HNT did not change the crystal type, according to the X-ray diffraction (XRD) study.     

Stimuli-responsive polymers and their applications in nanomedicine

This review focuses on smart nano-materials built of stimuli-responsive (SR) polymers and will discuss their numerous applications in the biomedical field. The authors will first provide an overview of different stimuli and their corresponding, responsive polymers. By introducing myriad functionalities, SR polymers present a wide range of possibilities in the design of stimuli-responsive devices, making use of virtually all types of polymer constructs, from self-assembled structures (micelles, vesicles) to surfaces (polymer brushes, films) as described in the second section of the review. In the last section of this review the authors report on some of the most promising applications of stimuli-responsive polymers in nanomedicine. In particular, we will discuss applications pertaining to diagnosis, where SR polymers are used to construct sensors capable of selective recognition and quantification of analytes and physical variables, as well as imaging devices. We will also highlight some examples of responsive systems used for therapeutic applications, including smart drug delivery systems (micelles, vesicles, dendrimers...) and surfaces for regenerative medicine.     

Preparation of phytoncide-emitting nylon/PP sheath/core fiber and the release profile of phytoncide

Phytoncide, a volatile essential oil produced by plants and trees, has not only anti-microbial activity, but also a stress relieving effect. We prepared a sheath/core type melt-spun fiber that releases phytoncide for a prolonged time. The fiber is comprised of a nylon sheath and a polypropylene (PP) core material. Phytoncide-containing microcapsules are embedded within the core part. The phytoncide microcapsule-containing nylon/PP sheath/core (M-Ny/PP) fiber has suitable mechanical properties for textile application. The phytoncide release from the microcapsule-containing the PP fiber (M-PP) reached a plateau level after 4 days and maintained that level for an additional 7 days, indicating a zero-order release after the initial burst. The M-Ny/PP fiber emitted the volatile phytoncide even though the fiber was spun at 250 °C. The release of phytoncide decreased in the M-Ny/PP fiber compared to the phytoncide microcapsule-containing PP (M-PP) fiber due to the dense sheath layer.     

Preparation of hybrid AHO-POSS/polypropylene nanocomposite monofilaments by radiation induced grafting

The Allyl-heptaisobutyl-polyhedral Oligomeric Silsesquioxane (AHO-POSS) grafted polypropylene (PP) nanocomposite monofilaments were prepared by γ-ray irradiation induced grafting. The structure and properties of physically blended and γ-ray irradiated AHO-POSS/PP nanocomposite filaments were investigated by FTIR, wide-angle X-ray diffraction (WAXD), Thermo-gravimetric Analysis and mechanical property studies. Chemical bonding of AHO-POSS with PP after γ-ray irradiation was confirmed by FT-IR spectroscopy. Grafting resulted in change in mechanical and thermal properties and the extent of change was critically dependent on loading of AHO-POSS in PP and radiation dose level. In general, tensile strength decreased almost continuously with increase in radiation dose whereas thermal stability increased upto a radiation dose of 5 kGy and then decreased. The loss in tensile strength was caused due to chain scission, cross linking and loss in orientation.     

我国植物纤维复合材料的发展现状及展望

综述了近年来我国植物纤维复合材料的发展现状及特点,并根据基体材料和增强体材料进行初步分类。简要概括了植物纤维复合材料的应用领域,总结了我国植物纤维复合材料的发展趋势。     

Fabrication of novel multifunctional hybrid materials for PET/PA6 nonwoven fabrics finishing

A series of some novel hybrid materials prepared via a sol-gel process have been synthesized from methyltrimethoxysilane and titanium n-butoxide with heterocyclic thiazole azo dyes. Silica/titania/thiazole azo dyes hybrid materials were synthesized via a sol-gel process with a precursor system. Alternatively, the heterocyclic thiazole azo dyes were catalytically processed by means of hydrolysis-condensation reactions with appropriate amounts of a mixture of vinyltriethoxysilane, methyltrimethoxysilane, and titanium n-butoxide at a fixed molar ratio. The structure of these hybrid silica/titania/thiazole dye materials was characterized by Fourier transform infrared (FT-IR) analysis. The surface morphology of processed PET/PA6 nonwoven fabrics was evaluated by scanning electron microscopy (SEM). SEM images showed uniform dyeing, thereby confirming the reaction of the hybrid materials with the PET/PA6 nonwoven fabrics. The water contact angle, washing fastness, color evenness, air permeability, and weatherability characteristics of the as-prepared dyed PET/PA6 nonwoven fabrics were subsequently evaluated. Results revealed improved weatherability and good water repellency. Further, it was also revealed that dyeing and finishing could be achieved in a single bath, which is advantageous to reduce processing costs.     

Scalable preparation of multiscale carbon nanotube/glass fiber reinforcements and their application in polymer composites

The introduction of carbon nanotubes (CNTs) into conventional fiber to construct a hierarchical structure in polymer composites has attracted great interest owing to their merits of performance improvement and multiple functionalities. However, there is a challenge for realizing the scalable preparation of the multi-scale CNT-glass fiber (CNTGF) reinforcements in practical application. In this work, we present a simple and continuous method of the mass production of multiscale CNT-glass fiber (CNT-GF) reinforcements. Scanning electron microscopy and thermo gravimetric analysis indicated ~1.0 wt% CNTs were highly dispersed on the whole fiber surface through a facile surfactant-assisted process. Such hybrid CNT-GF fillers were found to effectively enhance the stiffness, strength and impact resistance of polypropylene polymer. Increased storage modulus, glass transition temperature and crystallization temperature of the composites filled with the CNT-GF fillers were also observed in the differential scanning calorimetry and dynamic mechanical analysis compared with the composites containing the pristine GF fillers. Fracture surface analysis revealed enhanced interfacial quality between CNT-GF and matrix, which is likely responsible for improved performance of the hierarchical polymer composites.     

Preparation and properties of Nano-TiO2 photo-catalytic silk respirator paper

In order to obtain paper respirator with dust resistance performance and antibacterial property, silk photo-catalytic respirator paper was made by loading nano-TiO₂ photo-catalyst on silk based respirator paper. The pore structure, surface topography and TiO₂ distribution, and the filtration performance of silk respirator paper were studied by using a pore size meter (PSM), a field emission scanning electron microscope (FESEM), and a filter tester, respectively. In addition, the antibacterial property of silk respirator paper was also investigated. The results showed that the pore structure and filtration performance of silk respirator paper could be controlled by changing the degree of beating of silk pulp and the basis weight of silk paper. Silk respirator paper of 45 g/m² made from silk pulp having beating degree of 85 ^oSR had high filtration efficiency and appropriate filtration resistance. Nano-TiO₂ particles were mainly attached to the surface of silk paper, and the loading of nano-TiO₂ photo-catalyst resulted in a slight decrease in filtration resistance and filtration efficiency of silk respirator paper. It, however, improved the antibacterial property of silk respirator paper effectively.     

Isolation, characterization and biological evaluation of jellyfish collagen for use in biomedical applications

Fibrillar collagens are the more abundant extracellular proteins. They form a metazoan-specific family, and are highly conserved from sponge to human. Their structural and physiological properties have been successfully used in the food, cosmetic, and pharmaceutical industries. On the other hand, the increase of jellyfish has led us to consider this marine animal as a natural product for food and medicine. Here, we have tested different Mediterranean jellyfish species in order to investigate the economic potential of their collagens. We have studied different methods of collagen purification (tissues and experimental procedures). The best collagen yield was obtained using Rhizostoma pulmo oral arms and the pepsin extraction method (2-10 mg collagen/g of wet tissue). Although a significant yield was obtained with Cotylorhiza tuberculata (0.45 mg/g), R. pulmo was used for further experiments, this jellyfish being considered as harmless to humans and being an abundant source of material. Then, we compared the biological properties of R. pulmo collagen with mammalian fibrillar collagens in cell cytotoxicity assays and cell adhesion. There was no statistical difference in cytotoxicity (p > 0.05) between R. pulmo collagen and rat type I collagen. However, since heparin inhibits cell adhesion to jellyfish-native collagen by 55%, the main difference is that heparan sulfate proteoglycans could be preferentially involved in fibroblast and osteoblast adhesion to jellyfish collagens. Our data confirm the broad harmlessness of jellyfish collagens, and their biological effect on human cells that are similar to that of mammalian type I collagen. Given the bioavailability of jellyfish collagen and its biological properties, this marine material is thus a good candidate for replacing bovine or human collagens in selected biomedical applications.     

Preparation and characterization of nylon-6/gelatin composite nanofibers via electrospinning for biomedical applications

Easy fabrication, porosity, good mechanical properties, and composition controllable of the electrospun nanofiber mat make this material a promising candidate for wound dressing applications. In the present study, nylon6/gelatin electrospun nanofiber mats are introduced as novel wound dressing materials. The introduced mats were synthesized by electrospinning of nylon6 and gelatin mixtures, three mats containing different gelatin content were prepared; 10, 20 and 30 wt%. Interestingly, addition of the gelatin did not affect the mechanical properties of the nylon 6, moreover the mat containing 10 wt% gelatin revealed higher mechanical properties due to formation of spider-net like structure from very thin nanofibers (～10 nm diameter) bonding the main nanofibers. Biologically study indicates that gelatin incorporation strongly enhances the bioactivity performance as increasing the gelatin content linearly increases the MC3T3-E1 cell attachment. Overall, the obtained results recommend exploiting the introduced mats as wound dressing material.     

Effect of reinforcement and chemical treatment of fiber on The Properties of jute-coir fiber reinforced hybrid polypropylene composites

Present research investigates the mechanical properties of jute-coir fiber reinforced hybrid polypropylene (PP) composite with fiber loading variation and observes the effect of chemical treatment of fiber on property enhancement of the composites. Composites were manufactured using hot press machine at four levels of fiber loading (5, 10, 15 and 20 wt%). Fiber ratio’s were varied (jute:coir=1:1, 3:1 and 1:3) for 20 % fiber loaded composites. Both jute and coir fiber was treated using 5 % and 10 % NaOH solutions. Composites were also prepared using treated fiber with jute-coir fiber ratio of 3:1. Tensile, flexural, impact and hardness tests and Fourier transform infrared spectroscopic analysis were conducted for characterization of the composites. Tensile test of composite showed a decreasing trend of tensile strength and increasing trend of the Young’s modulus with increase in fiber loading. During flexural, impact and hardness tests, the flexural strength, flexural modulus, impact strength and hardness values were found to be increased with increase in fiber loading. All these properties enhanced with the enhancement of jute content except impact strength. 5 % NaOH treatment provided an improving trend of properties whereas, 10 % NaOH treatment showed the reverse one. The FTIR analysis of the composites indicated decrease of hemicelluloses and lignin content with alkali treatment.     

A study of mechanical behavior and morphology of carbon nanotube reinforced UHMWPE/Nylon 6 hybrid polymer nanocomposite fiber

We report a phenomenal increase in strength, modulus, and fracture strain of ultra high molecular weight polyethylene (UHMWPE) fiber by 103 %, 219 %, and 108 %, respectively through hybridizing this fiber with Nylon 6 as a minor phase and simultaneously reinforcing it with single-walled carbon nanotubes (SWCNTs). Loading of Nylon 6 and SWCNTs into UHMWPE was 20.0 wt% and 2.0 wt%, respectively. Hybridized fibers were processed using a solution spinning method coupled with melt mixing and extrusion. We claim that the enhancement in strain-to-failure of the nanocomposites is due to induced plasticity in the hybridized Nylon 6-UHMWPE polymers. The enhancement in strength and stiffness in the nanocomposites is attributed to the load sharing of the SWCNTs during deformation. Differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) studies showed that changes in percent crystallinity, rate of crystallization, crystallite size, alignment of nanotubes, sliding of polymer interfaces and strong adhesion of CNT/polymer blends were responsible for such enhancements.     

Preparation and characterization of glass fiber-coir hybrid composites by a novel and facile Prepreg/Press process

The present study explored the preparation of glass fiber-coir reinforced unsaturated polyester resin hybrid (GCU) composites with a novel Prepreg/Press fabrication process. Flexural, impact and thermal-mechanical properties of GCU composites were investigated. Coir reinforced unsaturated polyester resin (CU) composites was also prepared with the same process to explore the enhancement effect of glass fabric on the mechanical properties of coir-based composites. The effect of fabrication pressure on the mechanical properties of CU and GCU composites was examined. Micromorphology and interfacial reaction of the composites were analyzed. It is shown that GCU composites fabricated with the Prepreg/Press process have excellent flexural strength (185.0 MPa), MOE (18.3 GPa), and impact strength (67.2 kJ/m²). The mechanical properties of GCU composites increased with the increase of applied pressure up to 0.8 MPa in the Prepreg/Press process. However, further increase of applied pressure led to the decrease in mechanical properties. The addition of glass fabrics to GCU composites showed 419 % improvement in flexural strength, 708 % improvement in MOE and 562 % improvement in impact strength over coir-based composites. The micromorphology study proved that the poor interfacial bonding between coir and matrix led to the low mechanical properties of coir-based composites.     

Preparation and properties of flame-retardant viscose fiber containing phosphazene derivative

The object of this work is to develop a flame-retardant viscose fiber containing phosphazene derivative. Hexaphenoxycyclotriphosphazene (HPTP) was synthesized and applied to viscose fiber through wet spinning method, with alkyl polysaccharide glycoside as dispersant. Properties of the fiber were tested and discussed. All flame-retardant samples survived 3 ignitions, according to 45 degree slope burning method. Limiting oxygen index value of the flame-retardant fiber containing 16% flame retardant was 28.6 %. The number decreased to 27.5 % after 30 washing cycles. After burning, inflated carbonized coat was found on the fiber surface in scanning electron microscopy image. Thermal gravimetric analysis and differential scanning calorimetry results indicated that the primary decomposition of fiber was moved up by about 20°C, while secondary decomposition was delayed by around 46°C. Damage on mechanical properties of fibers was insignificant. The introduction of HPTP was compatible and the flame retardancy of viscose fiber was greatly improved with limited negative impact.