Chao Sheng Wang

Fabrication of Hierarchical Microporous Structures with Controlled Morphology and Topography

Co-continuous polymer blend has attracted broad interest in many technique fields due to its unique ability to be transferred into porous material with interconnected micro-channels. And combined with some surface patterning, it can provide material of hierarchical porous structure. A key challenge in the fabrication of material of desired morphology is the ability to control the interface movement. Here, we incorporate the thermo-geometrically controlled annealing and hot embossing to fabricate hierarchical microporous structures with well defined morphology and topography. Various novel structures demanded for many emerging applications can be created by judiciously using this newly developed technique.

Preparation and Characterization of Water-Base Transparent Flame-Retardant Ceramic Coatings for Wood via Sol-Gel Method

Transparent flame-retardant ceramic coatings were prepared via sol-gel method by siloxane and silica sol as the matrix, organophosphates (M102B) as the fire retardant agent, solvent and other additives. Results showed that such coatings had excellent physical and chemical properties. When the weight ratio of M102B reached 3% in the coatings and the cover weight reached 2g/100cm2 on the wood, the limit time of fire-endurance could get to 64 min. The decompose processes and formation of the flame-retardant coatings were investigated by TGA and FTIR.

Effects of Poly(Ethylene Glycol) Segment on Physical and Chemical Properties of Poly(Ether Ester) Elastomers

Poly (ether ester) elastomer, a segmented copolymer, recently has attracted a wide attention for its unique properties such as elasticity, low temperature impact resistance and chemistry resistance. In this work, a range of poly (ether ester) s were synthesized via a two-step polymerization method using poly (ethylene terephthalate) (PET) as rigid segment and poly (ethylene glycol) (PEG) as flexible segment. The effects of the molecular weight (1000-8000 g/mol) and the weight ratios with PEG (30/100-70/100) of PET segments on the performance of synthetic copolymers were investigated. The chemical structure, thermal properties and hydrophilic performance of the copolymers were respectively characterized. Additionally, the practical block ratios of PEG/PET were calculated by the 1H-NMR Spectra of the copolymer after Soxhlet extraction. Through the obtained results, it revealed that increasing the molecular weight or content of PEG could enhance the hydrophilic performance of the copolymers and reversely reduce its thermal stability. It was shown that the reactivity of PEG in the polymerization process was weakened when its molecular weight was above 4000 or weight ratio with PTA was higher than 60/100, subsequently affected the practical block ratios of PEG/PET in the resulting poly(ether ester)elastomers.

Preparation and Characterization of the Hydrophilic Copolyester

A series of hydrophilic copolyesters were prepared via copolymerization method with purified terephthalic acid (PTA), ethylene glycol (EG), 5-sodium suflo bis-(hydroxyethyl) isophthalate (SIPE) as the third monomer, and different content of polyols (FMA01) as the fourth monomer. The chemical structures of the hydrophilic copolyester were described by Fourier transform infrared spectroscopy(FTIR), and the thermal properties of the samples were studied by thermogravimetric analysis(TGA) and differential scanning calorimetry(DSC). The hydrophilic properties of the samples were measured by contact angle(CA) measurements. Results showed that such modified copolymers had excellent hydrophilic properties. When SIPE reached 3mol% and FMA01 reached 0.8mol%, the copolyester film turned its wetting property to hydrophilic with water contact angle of 53.7°.

Preparation and Characterization of Flame Retardant PET Fiber via Melt Blending

Poly(ethylene terephthalate) (PET) fiber with excellent flame retardant property was prepared with introducing a containing phosphorus flame retardant 10-(2’,5’-dihydroxyphenyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (ODOPB) into PET by melt blending method. The intrinsic viscosity of the modified PET was decreased after melt blending, indicated that ODOPB could promote the degradation of PET. The addition of ODOPB can increase the amount of carbon residue of PET, which can effectively reduce the heat transfer. The movement and regularity of PET molecular chain are affected by ODOPB, resulting in the reducing of the crystallization of PET. The Raman curves indicate that the addition of ODOPB can improve the regularity of carbon layer, which is conducive to achieve the effect of flame retardant. When the mass fraction of P is 0.7 %, the limiting oxygen index of sample reaches 32.4% and UL-94 vertical reaches V-2, the fiber fracture strength is 2.6 cN/dtex, which has excellent flame retardant and mechanical properties.

Preparation of Nano Cu-ZnO/PET Fiber for Antibacterial Application

Polyethylene terephthalate (PET) fiber is applied to clothing, home textiles and other fields because of its low cost, high strength, quick-drying and stable structure, etc. Polyester fiber generally doesn’t have the ability to kill bacteria, and it is a kind of porous material which is conducive to the microbial adhesion and spread of bacteria. In the present study, Cu-ZnO and its antibacterial PET fibers were prepared by sol–gel method and melt spinning, respectively. The structures and compositions of Cu-ZnO were characterized by X-ray diffraction (XRD) and Fourier transform-infrared (FT-IR) spectra. The crystallization and melting behavior of the PET/Cu-ZnO (0.05:1) composites were tested by differential scanning calorimetry (DSC) to determine the temperate of melt spinning. The morphologies and mechanical properties of antibacterial polyester fiber were studied by field emission scanning electron micrographs (FE-SEM) and strength machine, respectively. The antibacterial properties of the samples on E. coli and S. aureus were determined using powder inhibition zones and antibacterial rate. The results show that the fibers exhibited excellent antibacterial activity, it had obvious inhibiting effects on E. coli and S. aureus and the antibacterial rate were both above 90%.

Preparation and Characterization of Antibacterial Nylon 6 Fiber

Due to its excellent mechanical property, dye ability and skin affinity, PA6 has been widely used in apparel, home textiles, military products, etc. However, PA6 fiber is easy to breed bacteria and corroded by bacteria in humid environment. One of development tendency of functional PA6 fiber is to design and develop nylon 6 fiber with excellent antibacterial properties, which is also the research target of this paper. In the present investigation, ZnO antibacterial agent was prepared through sol-gel method, and antibacterial masterbatch was acquired via blending antibacterial agent with PA6 using a twin-screw, then antibacterial PA6 fiber was obtained through melt spinning. The thermal properties, crystallization property of antibacterial PA6 masterbatch were discussed. The effect of drawing ratio on fiber strength, elongation of break, orientation and crystallization was also investigated. The antibacterial properties of antibacterial agent and antibacterial PA6 fiber was analyzed by agar diffusion method. The results of Differential Scanning Calorimetry (DSC) suggests that the antibacterial agent causes the rise of crystallization temperature and crystallization rate. X-Ray Diffraction (XRD) and mechanical testing results reveal that the higher drawing ratio leads to higher orientation and strength of PA6 fiber, lower elongation at break. The addition of antibacterial agent increases the degree of orientation and crystallization, reduces the strength of fiber and tends to form α crystalline in PA6 fiber. Antibacterial tests show that antibacterial PA6 fiber has a good antibacterial performance against Staphylococcus aureus.

Preparation and Properties of Copolyesters Fiber with Flame Retardant and Anti-Droplet by In Situ Polymerization

Containing phosphorus compound is widely used in the modification of flame retardant polyester due to the excellent flame retardant properties. But it is difficult to solve the droplet problems, especially the polyester fiber. In this paper the copolyesters and fiber with flame retardant and anti-droplet were prepared using reaction containing phosphorus flame retardant [(6-Oxido-6H-dibenz [c, e] [1, 2] oxaphosphorin-6-yl) methyl] butanedioic acid (DDP) and silica sol by in-situ polymerization. The structure and properties of modification flame retardant were measured by nuclear magnetic resonance (NMR), thermal gravity analysis (TGA). The results indicated that the modification flame retardant was more suitable for polymerization. The TGA, limiting oxygen index (LOI), vertical flame test, and scanning electron microscope (SEM) were devoted to discuss the flame retardant properties. It suggested that the nanoSiO2 particles increased char residue, and the nanoSiO2 particles were conducive to the formation of dense stable carbon layer, inhibiting the expansion of the carbon layer to form holes, the nanoSiO2 particles improved the droplet of copolyester. The highest LOI of copolyester is 34.8±0.1%, the UL94 is V-0 grade. The copolyester fiber has excellent mechanical, flame retardant and anti-droplet. This can meet the requirement of household textile decoration and use.

Water Absorption Behavior in Poly(Ethylene Terephthalate)-Poly(Ethylene Glycol) Block Copolymer Matrix by Two-Dimensional Correlation Spectroscopy

The absorption behavior of water in poly (ethylene terephthalate)-poly (ethylene glycol) (PETG) block copolymers was investigated using the time-resolved FTIR-ATR (Fourier Transform Infrared Attenuated Total Reflection) spectra. The data was analyzed by two-dimensional correlation spectra (2D-COS), which provided relevant and complementary information on the absorption mechanism and the molecular interactions formed (H-bonding). It was found that there were two kinds of water molecules, named bound water and free water in absorption process. The delicate relationship between dynamic water absorption behavior and the morphology resulting from phase separation was also discussed. Furthermore, two-dimensional correlation analyses revealed that in the absorption process, water first diffuses into the continuous soft-rich PEG phase and then into the hard-rich PET domains, forming hydrogen bonds with-O-groups prior to that of free volume.

Fabrication and Characterization of Polyorganosiloxane Superhydrophobic Film by Sol-Gel Method

The polyorganosiloxane superhydrophobic film was fabricated via a sol-gel process followed by nano-silica(SiO2) sol and new organo-siloxane reagent 1,1,1,3,5,5,5-heptamethyl-3-[2-(trimethoxysilyl)-ethyl]-tri-siloxane(in brief as HPTETOs), the chemical structure of the polyorganosiloxane superhydrophobic were described by Fourier transform infrared spectroscopy (FT-IR), the superhydrophobic property of the treated sample was measured by contact angle (CA) measurements. It revealed that nano-silica and polyorganosiloxane formed 3D hydrophobic groups on the film; the film has turned its wetting property from hydrophilic to superhydrophobic with water contact angle of 143.7°.