Low add-on technologies have attracted more and more attention due to the shortage of water resources. In order to explore the mechanism of low add-on technologies, the states of water and the pore properties (pore size distribution, total pore volume, specific surface area, and the average of pore radius) of cotton fibers were investigated over a wide moisture range by using differential scanning calorimetry (DSC) based on the Gibbs–Thomson effect. A simple model of cotton fiber with various moisture ratios was given. Larger pores changed in size with the change of moisture ratio prior to smaller pores in both wetting and drying of cotton fibers. The information obtained could be used to explain the results of dyeing processes. Low add-on technology (wet pick-up 30–40%) was a favorable choice for surface treatment. Excellent surface performance of fabric could be obtained, and large amounts of water and energy could be saved by low add-on technology.

A novel phenylethynyl-terminated cyclotriphosphazene oligoimides (hexakis (4-phenyl acetylene imide phenoxy) cyclotriphosphazene, HPAIPC) was synthesized to solve the conflict between flame retardance and antidripping of poly(ethylene terephthalate) (PET). The PET/HPAIPC composites were prepared by direct melt compounding, and the flame-retardancy and antidripping properties of the composites were investigated. The results revealed that thermal stability, self-extinguishing ability, and inhibition of melt-dripping properties of PET/HPAIPC composites were obviously enhanced by the introduction of high-temperature auto-cross-linking cyclotriphosphazene oligomides into polyester. All results of rheological analyses, pyrolysis products, and the morphology of the char demonstrated that the HPAIPC could exhibit a greater complex viscosity and enhance the physical barrier effect retarding the flammable gases, heat flux, and flame.

•The uniform deposition of copper nanoparticles are formed by the in-situ reduction of dopamine.•The fabric has superhydrophobicity after 30 washing cycles and after dyeing.•The fabric has high antibacterial activity against E. coli after 50 washing cycles and after dyeing.A simple two-step impregnation method was used to prepare copper nanoparticles coated cotton fabric. In which, dopamine firstly self-polymerized to polydopamine membrane on the cotton fabric surface, then copper nanoparticles were obtained and bound onto the cotton fabric using polydopamine as a reductant and binder. Field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS) and Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES) were used to observe the surface morphology and analyze the elemental composition as well as their surface chemical states of all samples. The results confirmed the formation of polydopamine film and copper nanoparticles. The results of contact angle measurements and antibacterial tests showed that the modified cotton fabrics had durable sticky superhydrophobicity and considerable antibacterial activity.

A new process to prepare L-lactic acid based polymer with high molecular-weight was established. In this process, the carboxyl terminated poly (L-lactic acid) (PLLA) prepolymer was first synthesized via polycondensation of L-lactic acid and a little adipic acid, and then the molecular weight of PLLA was increased by a chain-extending reaction using bisphenol-A epoxy resin as a chain extender. In situ FTIR was used to characterize the activity of reaction between epoxy groups at the end of bisphenol-A epoxy resin and carboxyl groups at the end of PLLA prepolymer, and the results showed that the reaction was of high activity. The weight-average molecular weight of prepared L-lactic acid based copolymer (PLLA-co-BisA ER) was up to 210,000 at an optimum synthetic condition. The thermal property and crystallization behavior of prepared copolymer were also studied.

Thermoplastic biodegradable composites based on ramie fibre (RF) and a poly(l-lactic acid)-poly(ε-caprolactone) (PLLA-PCL) matrix was manufactured using the in situ polymerization method. In order to improve the compatibility and strengthen the interface in natural fibre composite materials, the RF was firstly treated by coupling agents. Then the RF reinforced thermoplastic PLLA-PCL composite was prepared by in situ polymerization of PLLA oligomer with NCO-terminated PCL prepolymer. The effect of fibre length and fibre content on tensile strength and impact strength of this natural-fibre-reinforced biodegradable composite (PLLA-PCL/RF) was discussed, including the influence of the use of silane coupling agent (KH550) for improved interfacial adhesion. The results showed that the tensile strength and impact strength of PLLA-PCL/RF were highest when the RF length was 5-6mm, RF content was 45% and with KH550 as surface treatment agent of RF.