No abstract

In the current study, amino-terminated hyperbranched polymers (NH2-HBP) were synthesized by Michael addition reaction in which N, N’-methylene bisacrylamide (MBA) and diethylene triamine (DETA) were used as raw materials, and water was used as a solvent. Reaction temperature, raw material ratio, and reaction time were optimized via single-factor experiments in which the production rate and primary amino content were used as indexes. The results showed that the mol ratio of MBA to DETA was 1:1.1, the temperature was 70°C, and reaction time was 24 h. Under this condition, the primary amino content of NH2-HBP was 2.83 mmol/g, and the yield was 91.16%. The NH2-HBP structure was characterized by Fourier transform infrared spectroscopy and nuclear magnetic resonance. Moreover, the relative molecular mass distribution of NH2-HBP was also determined by gel permeation chromatography. As an active substance, NH2-HBP was grafted onto the polyamide microfiber synthetic leather used in clothes, and organic phosphine was used as a cross-linking agent. The change in dye uptake, surface chroma, and resistance to dry-rub and wet-rub fastness properties was discussed. When the NH2-HBP dosage was 5.5%, the dye uptake improved from 56.89% to 94.85% (an increase of almost 61%). The surface chroma also deepened, the dry-rub fastness improved from 3.0 to 4.5, and the wet-rub fastness improved from 2.5 to 3.5.

A facile synthetic method was used to prepare N-CQDs via the hydrothermal treatment of gelatin.

A “two-step method” was adopted to improve the hygienic property of polyamide microfiber synthetic leather base. Firstly, the amino-terminal hyperbranched polyamides (NH2-HBP) synthesized by N, N'-methylene bisacrylamide (MBA) and diethylene triamine (DETA) was cross-linked to microfiber synthetic leather base pretreated with formic acid, in which glutaraldehyde was the crosslinking agent. Secondly, Gelatin hydrolysate was cross-linked to the preliminary modified microfiber synthetic leather base by using glutaraldehyde as the crosslinking agent. The modified microfiber synthetic leather base was then obtained. Hygienic performances, mechanical properties, and the micro morphology were taken as indexes to optimize the dosages of glutaraldehyde and NH2-HBP. The results show that when the glutaraldehyde dosage was 1.1 times that of the primary amino groups (the primary amino group dosage was about 0.201 mmol/g), the modification effect improved greatly. In this condition, the water vapor permeability, hygroscopicity, tensile strength, and tear strength of the base were 0.7691 g/10 cm2·24 h, 3.357 mL/g·24 h, 18.79 N/mm2, and 103.18 N/mm, respectively. These values were 86.7%, 48.8%, 19.8%, and 2.69% higher than those of unmodified base, respectively. When NH2-HBP dosage was three times that of the primary amino groups, the modification effect also improved. In this case, the water vapor permeability, hygroscopicity, tensile strength, and tear strength of the base were 0.5761 g/10 cm2·24 h, 3.274 mL/g·24 h, 18.79 N/mm2, and 103.4825 N/mm, respectively. These values were 113%, 42.3%, 3.5%, and 2.98% higher than those of the unmodified base, respectively. Meanwhile, the SEM image of the modified base showed that fiber dispersion was greatly increased in this condition.

Leather retanning agents are of great meaning for the reactive competence and thermal, physical, and mechanical properties of treated leather fibers. For this motif, reactive amphoteric polyurethane with multialdehyde groups (AAPU) was prepared by a polyaddition reaction with isophorone diisocyanate, poly(tetrahydrofuran glycol), 2,4-dihydroxybenzaldehyde, 2,2-dihydroxymethyl propionic acid, and N-methyl diethanolamine as raw materials and was then used as a retanning agent to explore its effects on leather fibers. The structure of AAPU was confirmed by UV, Fourier transform infrared, and 1 H-NMR spectroscopy. An average particle size of 42.6 nm and an isoelectric point of 5.16 were determined. The thermal stability, physical and mechanical properties, and morphology of the AAPU-treated leather fibers and their reactivities to anionic materials were investigated. Because of the crosslinking effect of multisite covalent bonds, which resulted from reactions between the aldehyde groups in AAPU and the pendant amido groups from collagen fibers, and the role of the cationic groups in AAPU, the thermal stability of the treated leather fibers and their reactivity to anionic materials, such as dyestuffs and fatliquoring agents, were enhanced. Thus, the absorption rate of dyes was almost as high as 99.89%, and the physical and mechanical properties of the AAPU-treated final leather fibers were superior to those of the contrast.

Purpose -The aim of this paper is to develop a new method to predict the potential shrinkage of plain-knitted fabric. Design/methodology/approach -The presented method is based on deformable curve. The delivered plain-knitted fabric is represented as a deformable parametric curve, and the relaxed fabric can be reached by minimizing the energy of the curve. Compared to the delivered-knitted fabric, the length and width shrinkage percentages can be calculated accordingly. Findings -The new method is more convenient than the traditional trial and error method, and need less-input parameters than the STARFISH technique. Experimental results show that this method is feasible. Originality/value -This paper presents a new method for shrinkage prediction of plain-knitted fabric based on deformable curve and energy minimum. The work can be linked with shrinkage control in textile industry.

Recent studies have been conducted on the characteristics of volatile organic compound emissions; most of them are focused on wood-based building materials, scarcely mentioned about leather or leather imitates. The volatile organic compound emissions of these products may cause poor indoor (vehicle cabins included) air quality. This article takes formaldehyde as an example to study its diffusion in leather. The porous structure of leather was characterized by carrying out mercury intrusion porosimetry test. The formaldehyde diffusivities in leather was assessed by Blondeau et al.'s, Ataka et al.'s, and Xiong et al.'s models which represent parallel, equivalent, and series interconnection of pores, respectively, and validated through independent liquid inner tube diffusion film emission experiments. The results demonstrated that the fractal dimension of leather is 2.19, which indicated it is a porous medium with self-similar pore structure. Most of the pores in leather were macro pores with average diameter 16.56 μm which contributed to 95.9% of whole porosity and the meso pore with average diameter 0.60 μm which contributed to 4.1%. As far as the liquid inner tube diffusion film emission experiment shows, the Xiong model agrees much better with the experimental results than the other two. The two kinds of pores were considered to be serially connected. It is useful for predicting volatile organic compounds diffusion coefficient in a short time and can be applied to the design and development of low volatile organic compound emission leather or leather imitates within further research.