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In order to improve the wear-resistant properties of polymer composites, a common approach is to introduce high-strength or lubricating components in composites, but the mechanical properties of composites are generally significantly reduced. It is still a challenge to obtain excellent wear resistance as well as good mechanical properties. In this work, a new ultrahigh molecular polyethylene (UHMWPE)/polycrystalline mullite fiber (PMF) composite was developed to simultaneously improve the tribological properties and the mechanical properties. The wear rate (K0) of UHMWPE/PMF reduced drastically [≈10–5 mm3/(N·m)] to about 2.5% of K0 of original UHMWPE. And the tensile strength and the elongation at break of UHMWPE/PMF remained at 97.0% and 90.0% of pure UHMWPE, respectively. These improvements are related to the higher crystallinity of UHMWPE/PMF (UHMWPE/PMF: 49.2%; UHMWPE: 41.2%), the larger crystallite sizes (UHMWPE/PMF: 21.0 nm; UHMWPE: 12.0 nm), and the high hardness and excellent mechanical strength of PMF. The simple processing of UHMWPE/PMF composites by adding PMF to increase the tribological properties is low cost and attractive, which has a great potential application in the fabrication of highly wear-resistant materials. [ABSTRACT FROM AUTHOR]

Carbon nanotube (CNT) aqueous suspensions are attracting considerable attention in conductive, antistatic, electromagnetic shielding coatings and films owning to their environmental safety. However, stable CNT suspensions are difficult to prepare because of the remarkable entanglement between CNTs and their intrinsic hydrophobicity. A new class of amphiphilic dispersants—pyrene butyric acid polyethylene glycol monoester (Py-mPEG)—were prepared through the esterification reaction between 1-pyrene butyric acid and polyethylene glycol monomethyl ether. Varieties of multi-walled carbon nanotubes (MWCNTs) aqueous suspensions were prepared by ultrasonic method using the following dispersants: Py-mPEG, sodium dodecyl benzene sulfonate (SDBS), Py-mPEG/Al2O3, and SDBS/Al2O3. The concentrations of suspended MWCNTs were determined by UV–vis absorption spectroscopy, and the state of suspensions was characterized by scanning electron microscopy (SEM). The non-covalent interactions between MWCNTs and Py-mPEG were investigated by fluorescence emission spectroscopy, and density functional theory calculations. The results showed that MWCNTs were more readily dispersed in Py-mPEG solutions than in SDBS solutions, whereas the Al2O3 particles could further improve the dispersion effect. Particularly, the MWCNT concentration reached 1.363 mg/mL using Py-mPEG (1000 ppm)/Al2O3 (particle size: 5–6 µm) as dispersant. A large number of individual MWCNTs were observed from the SEM images of the suspensions. A diffusion experiment on ink showed that the Al2O3 particles with particle size of 5–6 µm were highly responsive to ultrasound. The entangled MWCNTs could be disintegrated by the collision of particles. [ABSTRACT FROM AUTHOR]

The adhesion foundation of seawater organisms can be eliminated by killing the bacteria on the surface of objects in seawater. Thus, 4-bromo-2-(4-chlorophenyl)-5-(trifluoromethyl)-1H-pyrrole-3-carbonitrile (Econea) was selected as the core functional group to conduct the solution grafting reaction with the epoxy-containing acrylate copolymer (EA) to yield the marine antifouling paint, EA–Econea. UV absorption spectrum, Fourier transform infrared spectrum (FTIR) and energy dispersive spectrometer (EDS) analyses verified that Econea was exactly bonded to the EA molecular chain. Furthermore, the antibacterial test, confocal laser scanning microscope (CLSM), and antifouling experiments confirmed that when the mass fraction of Econea in the reaction reaches 0.5%, the coating affords 99.9% antibacterial effect on Escherichia coli and Staphylococcus aureus. The Econea and EA molecular chain combination cannot be easily broken, which lays the foundation for the long-term antifouling performance of the coating. A stainless steel plate coated with EA–Econea was immersed in a river rich in microorganisms for two months, and the plate was not contaminated. [ABSTRACT FROM AUTHOR]

An acrylic copolymer containing epoxy groups was synthesized by free radical polymerization of glycidyl methacrylate, methyl methacrylate and butyl acrylate. Afterwards, polyhexamethylene guanidine hydrochloride (PHMG) was chemically bonded with the resin through a reaction between the epoxy groups of the resin and the amino groups of PHMG to generate non-leaching and permanent antimicrobial acrylic coating. When the content of PHMG reaches 1.0 wt%, the inhibition factors against E. coli and S. aureus were respectively 99.992% and 99.994%, and the antimicrobial coating retains an excellent antimicrobial property even after being laundered with detergent solution. Moreover, the hydrophilicity of the antimicrobial coating was increased after the introduction of polar PHMG. [ABSTRACT FROM AUTHOR]

Many efforts have been devoted to developing functional poly(ethylene terephthalate) (PET) due to its special biomedical applications in surgical meshes, heart valves, vascular grafts, artificial ligaments, etc. However, for antimicrobial PET the release of antimicrobial component remains a concern. In this work, an antimicrobial compound with terminal epoxy group was synthesized by ethylene glycol diglycidyl ether (EGDE) and polyhexamethylene guanidine hydrochloride (PHMG). Then, EGDE-PHMG was chemically bonded with PET surface through a reaction between the epoxy group of EGDE-PHMG and the amino group of aminated PET to generate non-leaching and permanent antimicrobial PET. The content of PHMG on PET surface, morphology and hydrophilicity of surface, antimicrobial activity and mechanical property of PET were investigated. The amount of EGDE-PHMG on PET surface reached at 3.96 nmol/cm2, resulting in excellent antimicrobial activities against Escherichia coli and Staphylococcus aureus with above 99.99% of inhibition rates. Due to the good hydrophilicity, excellent antimicrobial property, non-leaching characteristic of antimicrobial component and good mechanical properties, the as-prepared antimicrobial PET was promising in the biomedical applications. [ABSTRACT FROM AUTHOR]

Nonbiodegradable features and the lack of antimicrobial activity for conventional synthetic polymer-based packaging materials remain as extensive concerns for environmental issues and food safety. In this work, an antimicrobial copolymer PHGH-PPGDE was synthesized via a reaction between polyhexamethylene guanidine hydrochloride (PHGH) and poly(propylene glycol)diglycidyl ether (PPGDE). The obtained PHGH-PPGDE was amphiphilic, antimicrobial and reactive due to the terminal reactive group. The TEM images indicated that PHGH-PPGDE formed aggregated particles dispersed in water. The antimicrobial paper was conveniently prepared by dip-coating a paper matrix in the PHGH-PPGDE aqueous dispersion, or mixing the dispersion with pulp. The resultant paper showed excellent antimicrobial activities against Escherichia coli and improved durability for the nonleaching effect. [ABSTRACT FROM AUTHOR]

The branching and cross-linking of poly(ethylene terephthalate) were investigated using two chain extenders: glycidyl methacrylate-styrene copolymer (GS) and poly(butylene terephthalate)-GS (PBT-GS) in order to improve the melt viscosity and melt strength of poly(ethylene terephthalate). An obvious increase in torque evolution associated with chain extending, branching and cross-linking was observed during the process. The properties of modified poly(ethylene terephthalate) were characterized by intrinsic viscosity and insoluble content measurements, rheological and thermal analysis. The intrinsic viscosity and rheological properties of modified PET were improved significantly when using PBT-GS, indicating that PBT-GS should be a better chain extender. Good foaming of poly(ethylene terephthalate) materials were obtained using supercritical CO as blowing agent. The average cell diameter and cell density were 61 μm and 1.8 × 10 cells/cm, respectively. [ABSTRACT FROM AUTHOR]

The comb-like ionenes with aliphatic side chains were prepared and blended with a low density polyethylene (LDPE) for enhancing the antistatic and antimicrobial properties. The resulting blends were well characterized, particularly based on the surface resistivity (ρ) which revealed the antistatic properties of LDPE/ionene blends. The results showed that the values of ρ decreased 1-5 orders of magnitude after the ionenes were added. Various influencing factors on ρ, including ionene structures, ionene content, and humidity were investigated in detail. Furthermore, the surface and inner structures of resulting blends were characterized by ATR-FTIR and SEM along with water contact angle measurements. The antimicrobial activities of the ionenes and the blended sheets were assessed based on the minimal inhibitory concentration (MIC) values against E. coli and the growth inhibition of E. coli determined by means of a membrane adhering-colony counting method. The results indicated that the ionene with 4-carbon side chains had the lowest MIC value (7.8 μg/mL) and the corresponding blend reached 99.9 % of growth inhibition. [ABSTRACT FROM AUTHOR]