Continuous photografting of HEMA onto polypropylene fabrics with benzophenone Photoinitiator

Continuous photografting onto polypropylene fabrics in the absence of inert gases was carried out to improve hydrophilic property of PP fabrics, which was padded with a formulated solution of 2-hydroxyethyl methacrylate(HEMA) and benzophenone as a monomer and a photoinitiator, respectively. The grafting yield increased with increases in benzophenone concentration up to 30 % on the weight of the monomer and UV energy up to of 38 J/cm², while 30 % HEMA concentration was optimal for the grafting efficiency. The physicochemical properties of the grafted PP fabrics were monitored by FT-IR, SEM, zeta potential, and dyeability to a cationic dye. The grafting increased O_1s/C_1s content and remarkably produced more negative zeta potentials compared with the pristine PP fabric. Also the grafted PP showed the increased dyeability to cationic dyes with increasing graft yield resulting from the enhanced electrostatic interaction between the dyes and negatively charged surface of the grafted PP fiber. In addition, improved hydrophilic property of grafted PP fabrics was ascertained by more rapid water wetting time and higher water absorbency.     

Crystallization and Luminescence Properties of Polypropylene Fiber Containing Rare Earth Aluminates and a Sorbital Derivative Nucleating Agent

Polypropylene (PP) fibers with a sorbital derivative nucleating agent (SDN) and rare earth aluminates (SrAl₂O₄:Eu²⁺,Dy³⁺) were prepared via melt compounding and melt-spinning. Non-isothermal crystallization kinetics and luminescence properties of PP and luminous PP fibers were studied by differential scanning calorimetry (DSC), polarized optical microscopy (POM), and decay of the afterglow test. The crystallization temperature determined by DSC increased with the addition of the nucleating agent during the cooling process from 200 °C. The Jeziorny model successfully described the non-isothermal crystallization behavior of the luminous PP with various SDN contents. The crystal grain size and morphology of the sample with the SDN was different from that without nucleating agent. The luminous PP fabric having high initial brightness intensity, approximately 461 mcd g^-1m^-2, can be prepared with addition of 10 wt% of rare earth aluminates and 0.5 % of SDN.     

Green and Efficient Synthesis of an Adsorbent Fiber by Plasma-induced Grafting of Glycidyl Methacrylate and Its Cd(II) Adsorption Performance

A new chelating adsorbent for the removal of Cd(II) from aqueous solution, PP-g-GMA-DETA fibers, is prepared by plasma induced grafting of glycidyl methacrylate (GMA) onto the surface of polypropylene (PP) fibers, followed by modification with diethylenetriamine (DETA). The effects of grafting parameters on the grafting degree are investigated. Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy prove the successful grafting of GMA onto the surfaces of PP fibers and the subsequent conversion of epoxy groups of grafted GMA to amine groups, on reaction with DETA. The adsorption performances of Cd(II) by the chelating fibers are evaluated in detail. Kinetic and isothermal parameters are also evaluated. The data fit well with the pseudo-second order and Langmuir isotherm model, respectively. The maximum adsorption capacity of Cd(II) is 46.47 mg g^-1 and the prepared fibers show selective adsorbability towards target Cd(II) in presence of competing Mg(II) ions.     

The manufacture and Physical properties of Hanji Composite nonwovens utilizing the Hydroentanglement process

This study aims to develop the new Hanji paper composite nonwovens that positively affect the antimicrobial activity, deodorization, and comfort functionality of natural materials of cotton and rayon that have high consumer preference and to manufacture new sanitary goods and facial mask sheets utilizing the hydroentanglement process. The results of the study through the evaluation analysis of functionality and properties of the composite nonwovens developed in this study are as follows. The manufactured composite nonwovens have improved functionalities of absorption velocity, antimicrobial activity, and deodorization from the base materials of C45 (Cotton (45 g/m²)) and R53 (Rayon/PET (53 g/m²)). Also, physical properties such as tensile strength, breaking extension, and tearing strength have improved significantly. The texture of composite nonwovens of Mulberry 70 %/Pulp 30 %(15) of Hanji paper weight 15 g/m² with base material did not show a significant difference compared to the nonwovens of C45 and R53. However, the soft texture of composite nonwovens of Mulberry 70 %/Pulp 30 %(25) of Hanji paper weight 25 g/m² with base material showed somewhat of a decrease compared to the nonwovens of C45 and R53. When considering the marketability, the composite nonwovens of Mulberry 70 %/Pulp 30 %+C45 and Mulberry 70 %/Pulp 30 %+R53 were estimated to be a positive development for use in female sanitary products and facial mask sheet products. These newly developed Hanji composite nonwovens could contribute to the development of high value added products that would satisfy the consumers.     

Characterization and Biotechnological Potential of Extracellular Polysaccharides Synthesized by Alteromonas Strains Isolated from French Polynesia Marine Environments

Marine environments comprise almost three quarters of Earth’s surface, representing the largest ecosystem of our planet. The vast ecological and metabolic diversity found in marine microorganisms suggest that these marine resources have a huge potential as sources of novel commercially appealing biomolecules, such as exopolysaccharides (EPS). Six Alteromonas strains from different marine environments in French Polynesia atolls were selected for EPS extraction. All the EPS were heteropolysaccharides composed of different monomers, including neutral monosaccharides (glucose, galactose, and mannose, rhamnose and fucose), and uronic acids (glucuronic acid and galacturonic acid), which accounted for up to 45.5 mol% of the EPS compositions. Non-carbohydrate substituents, such as acetyl (0.5–2.1 wt%), pyruvyl (0.2–4.9 wt%), succinyl (1–1.8 wt%), and sulfate (1.98–3.43 wt%); and few peptides (1.72–6.77 wt%) were also detected. Thermal analysis demonstrated that the EPS had a degradation temperature above 260 °C, and high char yields (32–53%). Studies on EPS functional properties revealed that they produce viscous aqueous solutions with a shear thinning behavior and could form strong gels in two distinct ways: by the addition of Fe²⁺, or in the presence of Mg²⁺, Cu²⁺, or Ca²⁺ under alkaline conditions. Thus, these EPS could be versatile materials for different applications.     

Characterization of plant and animal based natural fibers reinforced polypropylene composites and their comparative study

Natural fibers are largely divided into two categories depending on their origin: plant based and animal based. Plant based natural jute fiber reinforced polypropylene (PP) matrix composites (20 wt% fiber) were fabricated by compression molding. Bending strength (BS), bending modulus (BM), tensile strength (TS), Young’s modulus (YM), and impact strength (IS) of the composites were found 44.2 MPa, 2200 MPa, 41.3 MPa, 750 MPa and 12 kJ/m², respectively. Animal based natural B. mori silk fiber reinforced polypropylene (PP) matrix composites (20 wt% fiber) were fabricated in the same way and the mechanical properties were compared over the silk based composites. TS, YM, BS, BM, IS of silk fiber reinforced polypropylene composites were found 55.6 MPa, 760 MPa, 57.1 MPa, 3320 MPa and 17 kJ/m² respectively. Degradation of composites in soil was measured upto twelve weeks. It was found that plant based jute fiber/PP composite losses its strength more than animal based silk fiber/PP composite for the same period of time. The comparative study makes it clear that mechanical properties of silk/PP composites are greater than those values of jute/PP composites. But jute/PP composites are more degradable than silk/PP composites i.e., silk/PP composites retain their strength for a longer period than jute/PP composites.     

Transparent Polycaprolactam Electrospun Nanofibers Doped with 1,10-phenanthroline Optical Sensor for Colorimetric Determination of Iron (II) and Vitamin C

A novel optical chemical sensor based on a transparent electrospun nanofibrous scaffold, composed of polycaprolactam (PA6) and 1,10-phenanthroline (Phen), deposited on a glass slide and impregnated with polyvinyl alcohol (PVA) was coupled with UV-vis spectrophotometry and used for colorimetric determination of ferrous ion (Fe²⁺) and ascorbic acid (AA). The electrospun nanofibers were characterized using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) techniques. The main factors affecting performance of the optical sensor (PA6-Phen/PVA@glass) including Phen dosage, pH of sample solution, electrospinning time, polymer solution flowrate, electrospinning voltage, and PVA amount were investigated and the related optimum values were obtained. The analytical merits of the sensor for quantitative determination of Fe²⁺ and ascorbic acid was evaluated. The limit of detection (LOD) and limit of quantification (LOQ) for Fe²⁺ were 1 and 3 μg mL^-1, respectively. The linear dynamic range (LDR) was 3–150 μg mL^-1 with the determination coefficient (R²) of 0.991. The relative standard deviation (RSD %, n=3) for a solution of 60 μg mL^-1 was 5.4 %. For determination of AA, LOD and LOQ were obtained equal to 0.5 and 2 μg mL^-1, respectively. The linear dynamic range was in the 2–200 μg mL^-1 range with a R2 of 0.994. The RSD % at 100 μg mL^-1, n=3) was equal to 7.0 %. The sensor was applied successfully to the detection of Fe(II) and AA in real water samples and aspirin tablets.     

Graft copolymerization of acrylamide onto rayon by chemical and radiation methods

The inherent properties of rayon fibre have been changed with additional properties through graft copolymerization of acrylamide, AAm, by chemical method using ceric ammonium nitrate/nitric acid, (CAN/HNO₃), as a redox initiator and γ-radiation induced mutual method. Reaction conditions such as monomer and initiator concentration, liquor ratio, temperature and time of reaction, amount of radiation dose have been optimized with respect to percentage of grafting. Maximum percentage of grafting (Pg), (40 %) using CAN/HNO₃ was obtained at [CAN]=31.92×10^?3 moles/l, [HNO₃]=79.36×10^?2 moles/l, [AAm]=14.07×10² moles/l in 20 ml of H₂O at 45 °C within 120 min while in case of radiation induced method, maximum Pg (30 %) was obtained at higher monomer concentration (28.14×10^?2 moles/l) and time (180 min) in 10 ml of H₂O at room temperature with total dose exposure of 11.178 kGy. The graft copolymers were characterized by FTIR, thermogravimetric and scanning electron micrographic analysis. Swelling behaviour in water, methanol, ethanol, acetone and DMF and dyeing and flame retarding properties of rayon fibre and grafted rayon fibre were investigated. Percent dye uptake (71.8 %) was found to be higher than that observed for the pristine fibre (57.4 %) and the grafted fibre after post phosphorylation reaction showed excellent flame retarding properties.     

Manufacturing and analyses of wet-laid nonwoven consisting of carboxymethyl cellulose fibers

Carboxymethyl cellulose (CMC) is a cellulose derivative having water-soluble property, biodegradability, and biocompatibility. It has been used in various medical applications as forms of gel, film, membrane, or powder. In this study, composite CMC nonwovens were produced, by a wet-laid nonwoven process, to improve the wet strength of carboxymethyl cellulose nonwovens. Followed by preparing the CMC fibers from cotton fiber, the composite CMC nonwovens composed of CMC fibers and PE/PP bicomponent fibers were manufactured by using 85/15 % v/v of ethanol/water solution as a dispersion medium. Structural analyses of CMC fibers, such as XRD, TGA, FT-IR, and degree of substitution indicated that CMC fibers were successfully produced. The wet strength of CMC nonwoven was dramatically increased by blending with the PE/PP fibers without sacrificing the key properties for wound dressing materials such as liquid absorption, gel blocking and liquid retention. It is expected that the composite CMC nonwovens will be a good candidate for wound dressing materials for mild exudate condition.     

Study on melt-blown processing,web structure of polypropylene nonwovens and its BTX adsorption

Petroleum hydrocarbons can have adverse impacts on the environment and human health especially when they exist in the form of emulsion and aqueous solution. Nonwovens prepared by melt-blown method are a potential candidate for the removal of petroleum hydrocarbons. In this study, the processing-structure-oil sorption relationships of the PP (polypropylene) melt-blown nonwovens were investigated. Besides, the kinetics and mechanism of toluene sorption in simulated fire-fighting wastewater on the optimized prepared PP melt-blown nonwovens were studied at the static and dynamic conditions. The results showed that the web structure can be effectively controlled by adjusting the hot air temperature, metering pump speed and distance of collector to die to obtain an average fiber diameter of 3.0-10.5 μm, surface area of 0.5-1.5 m²/g and porosity of 71.0-99.0 %. The sorption capacity for pure BTX medium increased with the decreasing fiber diameter and increasing porosity. The pseudo-second-order kinetic model better fitted the experimental data to describe the sorption of emulsified and dissolved form of toluene at static and dynamic conditions. The toluene sorption can be a combination of adsorption and capillarity, the contribution of which was about 1:14.     

POSS/polypropylene hybrid nanocomposite monofilaments by reactive extrusion

The Allyl-heptaisobutyl-polyhedral oligomeric silsesquioxane (AHO-POSS) grafted polypropylene (PP) was prepared by reactive extrusion and by physical blending routes. The structure and properties of physically blended and reactively blended POSS/PP nanocomposites were investigated by FTIR, wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), thermogravimetric analysis, SEM, spherutlic growth and mechanical properties studies. Chemical bonding of POSS with PP in reactive extrusion was confirmed by FT-IR spectroscopy. DSC and TGA studies showed that the thermal stability of AHO-POSS/PP nanocomposite prepared by reactive extrusion improved significantly as compared to only physically blended nanocomposites. WAXD studies showed decrease in crystallinity of the AHO-POSS/PP nanocomposites prepared by reactive extrusion. SEM studies showed aggregation tendency in case of physically blended AHO-POSS/PP nanocomposites. Spherulite growth studies show reactive blending retards spherulite growth in PP polymer.     

Surface modification of microporous polypropylene membrane by UV-initiated grafting with poly(ethylene glycol) diacrylate

Poly(ethylene glycol) diacrylate (PEGDA) was grafted, through UV-initiated grafting, onto a microporous polypropylene (PP) membrane in order to develop a moisture-sensitive porous structure. Based on the concentration of the PEGDA grafting solution, as well as other variables, the pores of the membrane were filled to varying degrees with cross-linked PEGDA hydrogel, decreasing the pore sizes. This decrease in pore size was highly dependent on the grafting degree (weight add-on of the grafted polymer) that was dependent upon grafting conditions. Grafting with PEGDA resulted in a microporous polypropylene membrane with increased hydrophilicity and moisture-responsive pores. The functional membrane can be used in biological protective materials to limit the transport of liquid-borne pathogens while maintaining moisture transport properties.     

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.     

Synthesis and characterization of acrylic fibers-<Emphasis Type="Italic">g</Emphasis>-polyacrylamide

Graft copolymerization of acrylamide onto commercial acrylic fibers was carried out using benzoyl peroxide as a free-radical initiator in aqueous medium within the 75–95 °C temperature range. In this study, the effects of initiator and monomer concentration, the amount of fiber, polymerization time, and temperature on the graft yield were investigated. The optimum concentration for initiator was found to be 2.0×10⁻³ mol/l and the optimum temperature of 85 °C. The activation energy of the reaction was calculated to as 35.81 kJ/mol at the temperature interval of 75–95 °C. The structures and morphologies characterization of grafted fibers was investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The thermogravimetric analysis data showed that the thermal stability of the acrylic fibers increased with graft yield. The scanning electron photographs showed that the homogeneous appearance of the fiber surface changed and a shell-like heterogeneous structure occurred at the surface with an increasing degree of grafting. The moisture content, water absorption, dyeability, and antimicrobial activity of grafted acrylic fibers were also reported. The results showed that grafting of polyAAm improved the moisture contain, water absorption, dyeability, and antimicrobial activity of fiber.     

Preparation and properties of polypropylene nanocomposites reinforced with exfoliated graphene

We have prepared a series of polypropylene/exfoliated graphene (PP/EG) nanocomposite films via efficient meltcompounding and compression, and investigated their morphology, structures, thermal transition behavior, thermal stability, electrical and mechanical properties as a function of EG content. For the purpose, EG, which is composed of disordered graphene platelets as reinforcing nanoscale fillers, is prepared by the oxidation/exfoliation process of natural graphite flakes. SEM images and X-ray diffraction data confirm that the graphene platelets of EG are well dispersed in PP matrix for the nanocomposites with EG contents less than 1.0 wt%. It is found that thermo-oxidative degradation of PP/EG nanocomposites is noticeably retarded with the increasing of EG content. Electrical resistivity of the nanocomposite films was dramatically changed from ∼10¹⁶ to ∼10⁶ Ω·cm by forming electrical percolation threshold at an certain EG content between 1 and 3 wt%. Tensile drawing experiments demonstrate that yielding strength and initial modulus of PP/EG nanocomposite films are highly improved with the increment of EG content.     

Study on structure and molecular dynamics of starch/poly(sodium acrylate)-grafted superabsorbent by <Superscript>13</Superscript>C solid state NMR

The domain-structure of samples containing a series of starch/poly(sodium acrylate)-grafted superabsorbents, pure starch, pure poly(sodium acrylate), and blend of starch/poly(sodium acrylate) has been studied by high-resolution solid-state ¹³C NMR spectroscopy at room temperature. The result shows that the crystallinity of starch decreases greatly in the grafted and blended samples. The values of ¹H spin-lattice relaxation time in rotating frame T _1ρ and ¹H spin-lattice relaxation time T ₁ shows that starch and poly(sodium acrylate) components in both grafted and blended samples have good compatibility in nanometer scale. In the ¹³C cross-polarization/magic-angle-spinning (CP/MAS) spectra, the chemical shift of the carbonyl group of poly(sodium acrylate) depends on the composition of the grafting samples, which indicates that the starch and the poly(sodium acrylate) components of the grafting samples exhibit better compatibility with each other than that of blended samples at molecular level.     

Synthesis and Application of Phosphorus-containing Flame Retardant Plasticizer for Polyvinyl Chloride

A novel phosphorus-containing flame retardant plasticizer (PFRP) derived from castor oil acid methyl ester (COME) was synthesized to substitute dioctyl phthalate (DOP) for plasticizing polyvinyl chloride (PVC) products. The chemical structures of PFRP were confirmed by fourier transform infrared spectroscopy (FTIR) and ¹H nuclear magnetic resonance (¹H NMR). Meanwhile, the plasticizing effect, flammability and thermal stability of plasticized PVC films were investigated by dynamic mechanical analyzer (DMA), limiting oxygen index (LOI) test, scanning electron microscope (SEM) and thermogravimetric analysis (TGA). As the PFRP content increasing from 0 wt% to 50 wt% amount of plasticizers, the plasticizing efficiency and the mechanical properties showed a slightly decreasing tendency compared with that of DOP, while the LOI value of plasticized PVC increased remarkably from 21.5 % to 25.2 %, showing a combined plasticizing efficiency and flame retardancy. SEM and TGA analysis indicated that PFRP had little effect on thermal stability but was effective to promote the formation of compact carbon residue.     

Graft copolymerization of granular allyl starch with carboxyl-containing vinyl monomers for enhancing grafting efficiency

Graft copolymerization of granular allyl starch with carboxyl-containing vinyl monomers using H₂O₂/Fe²⁺ initiator in aqueous dispersion was investigated for enhancing grafting efficiency of the copolymerization. The graft copolymerization was evaluated in terms of grafting efficiency, grafting ratio, and conversion of monomer to polymer. Influences of both allyl etherification of starch and structures of vinyl monomers used on the copolymerization were revealed. Variables such as molar ratio of Fe²⁺ to H₂O₂, initiator concentration, monomer concentration, polymerization temperature, and time of the graft copolymerization were also studied. It was found that allyl etherification of starch enhanced the grafting efficiency and grafting ratio evidently. Acrylic acid exhibited the greatest grafting efficiency and ratio for the copolymerization after starch was allyl-etherified. The copolymerization should be carried out under the protection of nitrogen gas at 30–35 °C for 3 h by using H₂O₂/Fe(NH₄)₂(SO₄)₂ as initiator. Preferred molar ratio of H₂O₂/Fe(NH₄)₂(SO₄)₂/anhydroglucose was in a range of 20/1/1000 to 60/3/2000.     

Optimizing the morphology,mechanical and crystal properties of in-situ polypropylene/polystyrene blends by reactive extrusion

In this study, in-situ polypropylene/polystyrene (PP/PS) blends were prepared via a reactive extrusion technique. Fourier transform infrared spectroscopy (FTIR) analysis confirmed the generation of polypropylene-grafted-polystyrene (PP-g-PS) copolymer in the reactive process. The morphology of the in-situ PP/PS blend tended to form a homogeneous structure, as observed by scanning electron microscopy (SEM). Owing to the introduction of PP-g-PS in the reactive extrusion, a remarkable enhancement of mechanical properties was achieved for the in-situ PP/PS blend. The elongation at break of the in-situ PP/PS blend with 15 wt% PS can reach 500 %, over 10 times higher than that of the normal PP/PS blend. Differential scanning calorimetry (DSC) showed an increased crystallization temperature of PP, which can be attributed to the heterogeneous nucleation effect of the PS and grafted PS. The analysis of wide angle X-ray diffraction (WAXD) indicated the development of beta crystals in the in-situ PP/PS blend.     

Mechanical and thermal properties of epoxy composites containing graphene oxide and liquid crystalline epoxy

The graphene oxide (GO) sheets are chemically grafted with γ-etheroxygentrimethoxysilane (KH560) and liquid crystalline epoxy (LCE) is synthesized from 4,4′-bis(2-hydroxyhexoxy)biphenyl (BP₂) and epichlorohydrin before being incorporated into epoxy matrix. Then we present a novel approach to the fabrication of advanced polymer composites from epoxy matrix by incorporation of two modifiers, which are grafted GO (g-GO) and LCE. The mechanical properties of epoxy composites are greatly improved by incorporating LCE/g-GO hybrid fillers. For instance, the addition of 3 wt% hybrid filler (2 wt% g-GO and 1 wt% LCE) into the epoxy matrix resulted in the increases in impact strength by 132.6 %, tensile strength by 27.6 % and flexural strength by 37.5 %. Moreover, LCE/g-GO hybrid fillers are effective to increase thermal decomposition temperature, glass transition temperature, and storage modulus by strong affinity between the fillers and epoxy matrix.