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Using methacrylic acid (MAA) and methyl methacrylate (MMA) as core monomers and polystyrene as the shell layer, polymer hollow microspheres (PHM) with good stability were prepared by using an alkali osmotic swelling method followed by spray drying. The average size of the PHM was approximately 875 nm. As a filling cross-linking agent, the PHM were added to a skin collagen material to disperse and fix, and a “polymer hollow microsphere composite collagen fiber” (PHCC) material was obtained. The results show that the PHM improve the mechanical strength, thermal stability and water resistance of the skin collagen material. The PHCC material has a low thermal conductivity (0.035 W/(K·m)) and excellent sound insulation performance and retains the soft and delicate touch of leather, which has application value in high-grade decorative materials and functional leather. This provides a new approach for developing flexible sound-absorbing thermal insulation materials.

High-end leather packaging material safe, environmentally friendly, and has a good market prospect. It is an interesting technology to solve the intrinsic functionalization of skin collagen packaging materials. Nano-Hydroxyapatite (HA) precursors solution with a specific 1.67 calcium to phosphorus ratio (Ca/P) were infiltrated into the three-dimensional collagen network matrix (3DCM) in situ growth based on goat skin pretreated with glutaraldehyde and the HAG-3DCM was obtained. After compression, a transparent film HAG-3DCM-was formed. Structural and functional characterization showed that the HAG-3DCM-CM film has good comprehensive performance, such as the tensile strength increased to 67 mPa from 28 mPa, the bending resistance increased from 5 cycles to 50 cycles and the swelling degree from 55% to 12%. HA disperses and fixes the three-dimensional collagen network matrix (3DCM) fibers, improves its stability against humidity and heat, and the thermal conductivity changed from 0.72 W/(K•m) to 0.65 W/(K•m). HAG-3DCM has a relatively high limiting oxygen index of 26.5%. This study demonstrates a new approach for preparing animal skin packaging materials with new application value.

The molecular weight of collagen-degrading polypeptides (CDPs) extracted using the alkali method from leather scraps must be expanded to improve its utilization effect. A novel polymer (CPP) was synthesized from tricyanogen chloride (TC) and CDP by mechanical force without water. According to the solution viscosity and content of water-soluble matter, the optimal condensation conditions of the

To control road dust pollution, a starch/organo-bentonite composite liquid dust suppressant (CLDS) was successfully prepared. Potato starch was dissolved with NaOH solution at room temperature, and then sodium bentonite modified with cetyltrimethylammonium bromide (CTAB-bentonite) was incorporated before polymerization reaction. The CLDS was characterized by XRD, FTIR, TG and SEM. Its properties, dust-suppression performances, dust removal effects and economic feasibility had also been evaluated. The results suggested CLDS presented a porous three-dimensional network structure with numerous layers and folds, and residual CLDS could form a protective solidified layer together with dust via high viscosity after solidification, which effectively enhanced the absorption of CLDS on dust, delayed its water evaporation, and inhibited dust diffusion under windy weather. CLDS also had good thermal stability and biodegradability due to the addition of CTAB-bentonite. 2.5 wt% CLDS can dramatically improve dust-suppression effect and overcome dust resuspension problem to save water consumption and bring economic benefits.

Air pollution by dust particles is a major health concern in urban and industrialized areas. Actual methods to reduce dust contamination, such as water spraying, are limited, calling for new dust suppressants. Here, we synthesized a liquid starch-based dust suppressant by grafting polyacrylic acid onto NaOH-pretreated potato starch and then crosslinking the grafted copolymer with gelatine. This dust suppressant was characterized by Fourier-transform infrared spectrometry, thermogravimetry, viscosity and contact angle measurements. We also measured permeability, water retention, anti-wind erosion and degradability of the dust suppressant. Field experiments tested the dust suppressing effect on particle matter 2.5 (PM2.5) and particulate particle matter 10.0 (PM10). We found that the addition of NaOH to potato starch improved the reaction efficiency and simplified the preparation process. The dust suppressant demonstrated excellent degradability, as shown by weight loss of 82 wt % after 60 days of soil burial, and the total dust suppression rates reached 57% for PM2.5 and 56% for PM10 in the field. Compared with spraying water, total dust suppression was higher by 25% and 33%, respectively.

Current computational fluid dynamic (CFD) models of spray dryers lack the capability to predict the structure of the agglomerates formed; loose or compact agglomerates. This is mainly due t...

The objective of this study was to develop the efficient methods for dialdehyde cellulose (DAC) production, in which periodate solution was used as oxidant, and an electrochemically assisted system was applied to achieve green, efficient, low-cost and sustainable oxidization of cellulose. The microcrystalline cellulose (MCC) was pre-treated by alkali or ultrasound, and then oxidized to prepare DAC in the electrolyzer with aqueous solution of sodium periodate. Finally, the DAC was obtained by centrifugation and lyophilization. The prepared DAC materials were characterized by FTIR, XRD and SEM, and analyzed via aldehyde group contents, crystallinity index, water solubility index and water retention value. The introduction of active functional groups promoted cellulose hydration and swelling. Compared to the ultrasound pretreatment, the alkaline pretreatment had a great influence on the water solubility index and water retention value of cellulose. The aldehyde group contents of DAC increased after the MCC was oxidized by sodium periodate in the electrolyzer. Electrochemically assisted oxidation significantly decreased the crystallinity of the DAC, and the surface structure was smooth and soft, which can be attributed to the electrochemically assisted reaction that could regenerate the spent periodate in anode electrolytic chamber. When DAC was prepared under optimal conditions (current density: 0.075 A/cm2, periodate concentration: 0.6 mol/L, reaction time: 30 min), the regeneration efficiency of spent periodate reached about 93.4%.

Nano-Hydroxyapatite precursors with calcium and phosphorus salts (Ca/P = 1.67) were introduced into a three-dimensional collagen network matrix (3DCM) based on goat skin pretreated with glutaraldehyde for in situ growth, and a functional HAG-3DCM board was obtained. After plasticity compression, a transparent protein plastic film was formed. Response surface methodology based on plasticity pressure conditions was used, and the strength, hardness and water resistance of the HAG-3DCM plastic film was significantly improved. This study demonstrates a new approach for the preparation of animal skin materials with new application value.

Low-molecular-weight keratin (LMWK) obtained from wool was employed as a wall material for the spray drying encapsulation of fish oil. Microcapsules with different LMWK contents were prepared, and their anti-ultraviolet performance and other features were studied. The results showed that LMWK was able to improve the encapsulation efficiency of fish oil because of its good emulsifying properties. When the LMWK content was increased from 0 to 10, 30 and 50%, the shelf life of the microcapsules under ultraviolet irradiation increased from 48 to 96 h, 144 h and 168 h, respectively. The strongest absorption efficiency of LMWK is shown in the UVc band. The chemical structure of LMWK did not change during an ultraviolet accelerating ageing test. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13197-020-04897-2) contains supplementary material, which is available to authorized users.

Structural induced heat transfer capability of waterborne polyurethane (WPU) membrane was investigated. Hereby, WPU emulsions were synthesized with series of combinations of 2,4-Diisocyanatotoluene (TDI), poly(propylene glycol) (PPG), Poly(ethylene glycol) (PEG), dimethylolpropionic acid (DMPA) and ethylene glycol (EG) for studied membranes preparation. In this study, optimal prepolymer components, hard segment content, hydrophilic fragments and thermal annealing treatment on membrane-forming process were performed to study the structural features of WPU and corresponding heat conduction. Regarding to the results of AFM, XRD and DSC analysis, we found heat conduction was tightly related to the status of phase behaviors in studied WPU membranes. That's because phonon propagation as one primary heat carrier in polymer matrix was closely depended on the morphology of polymer chains. Good phase separation behavior could conduce to form long-range, short-range and microcrystalline ordering in WPU through intermolecular force (e.g. hydrogen bond), further pave as a conductive path for heat transmitting.

Waterborne polyurethanes (WPUs) with different mass ratios of soft and hard segments were synthesized by toluene diisocyanate, polypropylene glycol (PPG) and ethylene glycol (EG). It was shown that the PPG-based WPU with a mass ratio of soft and hard segments of 3:2 expressed a highest thermal conductivity (similar to 0.374 W/m.K), but showed a lowest T-peel strength (21.55 N/25 mm). As the mass ratio of soft and hard segments increased to 4:1, the T-peel strength was increased to 136.14 N/25 mm and thermal conductivity was decreased to a lowest value (similar to 0.306 W/m.K). To gain more understandings a number of analytic were carried out, such as FTIR, TG, DSC, DMA, AFM and XRD. Furthermore, mechanical properties of the PPG-based WPU coatings were tested as well. A possible explanation for the change in properties is due to the degree of phase separation and crystallinity, which was increased with the increasing of hard segment content. As a result, the hard and soft segments formed orderly oriented stacked structures by owing to the increasing of phase separation.

For the sake of the safe and efficient cyclic utilization of chrome leather shavings (CLS), the temporary stabilization of CLS during the storage and transport processes was optimized. Afterwards, the large-scale stabilized CLS degradation and collagen degradation product (CDP) extraction were completed. In this research, hydroxyapatite (HAP) and calcium hydroxide (Ca(OH)2) were for the first time used as stabilizers in the stabilization of CLS. The results showed that both Ca(OH)2 and HAP displayed resistance to chrome leaching, but HAP provided better stabilization effect than Ca(OH)2. The optimized stabilization conditions giving lower chromium leaching concentration were selected: 2% HAP, temperature 300 °C, reaction time 60 min, and initially added water contents of 50%. The reason for HAP and Ca(OH)2 stabilization was proved by energy dispersive X-ray spectroscopy (EDS). Subsequently, the exploitation value of the stabilized CLS was described by large-scale experiment. The hydrolysis of stabilized CLS could obtain the collagen degradation product (CDP), which had 3.52% of free amino content and a molecular weight of 3.4~30 kDa. The filter residue was treated by 5% sulfuric acid solution extraction and pressure filtration again. The extraction solution and final filter residue were dried separately to obtain chromium-containing organic compounds (COP) and industrial gypsum. The COP, used as a filling for tannery, contains 9.37% Cr2O3 content and 90.6% organic content. The industrial gypsum contains 68.37% CaSO4, 0.13% Cr2O3, and 31.5% residual organic or inorganic compounds, which can be used in building materials. No waste water or solid waste was discharged in this experiment process.

With the respect to research the effects of polyethylene glycol (PEG, Mw = 1000), an ordered hydrophilic fragment, on thermal conductivity of waterborne polyurethane coatings (WPUCs), the PEG–polypropylene glycol (PPG, Mw = 2000)–based WPUCs (PEG-PPG-based WPUCs) were synthesized with different combinations of PEG and 2,2-bis(hydroxymethyl)propionic acid (DMPA). The total amount of hydrophilic agent was fixed. Experiment found that the PEG-PPG-based WPUC synthesized with 13% PEG and 2% DMPA showed a highest thermal conductivity (∼0.675 W/m‧K). The phase separation, crystallinity and thermal conductivity were increased with the increasing of PEG. A number of characterizations were carried out through FTIR, TG, DSC, DMA, AFM and XRD to study the association of chemical structures and thermal conductivity at the basis of multiple combinations. The results showed that the ordered PEG fragments incorporated into WPUCs could increase the crystallinity and thermal conductivity, which was owing to the more ordered structures formed in hard phase and soft phase, and that facilitated the phonon propagation in free pathways, as a result.

One chemical sand-fixing material based on graft copolymer of gelatin (G) extracted from leather solid wastes was studied in this work. G was extracted from leather solid wastes through the method of alkaline hydrolysis firstly, and then acrylamide (AM) and acrylic acid (AA) monomers were grafted onto the G to synthesis the graft copolymer (G-g-P(AM-co-AA)) by free-radical copolymerization. The graft copolymer was purified by solvent method, after that the purified G-g-P(AM-co-AA) was characterized by FTIR, TG–DTG and other analysis technology. The results indicated that both the adsorption peaks of gelatin’ amide bond and monomer existed in infrared spectrogram proved that the AM and AA monomers have grafted with G. The thermal stability of G was improved after reacted with AM and AA monomers, and the maximum decomposition temperature was about 380 °C. The G-g-P(AM-co-AA) has good storage stability, dilution stability and temperature resistance. And the product has excellent biodegradability, which reflected better environmental protection and safety property. The G-g-P(AM-co-AA) could be combined with sand particles, and formed a consolidation layer, which has a good water retention, anti-wind erosion and anti-water erosion. When the mass fraction was 3%, G-g-P (AM-co-AA) solution can meet the requirements of sand-fixation under conventional desert environment.

Urea-formaldehyde (UF) resin was modified by semi-liquefied bamboo to prepare plywood adhesive. The unliquefied bamboo fiber solid becomes the filler or putty in the bonding process and disperses the UF resin molecules effectively to improve the stability of the UF resin during storage. UF resin was modified by adding 25 wt% semi-liquefied bamboo (SLB) based on UF resin solids. The structure, morphology, thermal stability, rheological behavior and basic properties of the composite adhesives were investigated. The formaldehyde emission of the plywood made with UF containing SLB was lower than that of the plywood made from neat UF, while the modulus of rupture (MOR), modulus of elasticity (MOE) and bonding strength (BS) values increased by increasing the SLB content in the plywood, and the thermal stability of the composite adhesive decreased. The results indicate that the SLB-UF-25% composite adhesive is a good composite adhesive and reaches the national standard technical index of plywood bonding.

Waterborne polyurethanes (WPUs) have been pushing toward more multifunctional directions developing which is due to the more extensively utilized in the world. Obviously, electronic devices are becoming more miniaturization and intelligentialize, accompanying many problems (e.g., heat dissipating and heat aging) to resolve. Organic polymers are to be good substitute for metal substrate used in devices because of their excellent performances. However, due to the most of polymers are poor conductor of heat, so many researchers utilize the hybrid method to enhance thermal conductivity of composites, through the pathway formed by fillers connection to build heat networks for phonon conduction. In this study, we do some reviews of WPU/composites on heat conducting. We put a focus on the enhancement of thermal conductivity through the compatibility and feasibility of hybrid methods, which includes the physical and chemical modification with non-covalent and covalent bond interactions. Plus, referring to laboratory previous study of heat conduction, on which pure WPU possessed with short-range, long-range ordering and microcrystal structures can facilitate the phonon conduction with the improvement of thermal conductivity.

A biodegradable film based on gelatin extracted from chrome leather scrap was studied in this paper. According to the results of a variety of characterization, the extracted gelatin contains 13 kinds of amino acid; the chrome content is 30 mg/kg, mineral and salt content are both at low levels and the nitrogen content is 43.84%. Its molecular weight has been measured at about 6.5 kDa ∼26.6 kDa, and the average particle distribution appears to be 125 nm with a narrow distribution. When the extracted gelatin was modified with the β-cyclodextrin to prepare the biodegradable films, the β-cyclodextrin and gelatin blends can build up perfect compatibility and film-forming properties. Comparing to the gelatin film without β-cyclodextrin, the viscosity, biodegradability, thermal stability and physical properties of the β-cyclodextrin and gelatin blends in the present research were significantly increased, especially when the ratio of β-cyclodextrin to gelatin was 1:2, the biodegradation rates reached 81%, elongation at break 15.74% and the tensile strength 122.34 MPa. The blends show perfect swelling properties and overcome the rapid solubility drawback of extracted gelatin.

The conversion of biomass waste resources into value-added products is an interesting subject. In this paper, a functional biobased aerogel derived from waste bamboo fibres and gelatin was successfully developed. Hydrochloric acid, phenol, and leather shavings were used as additives, and under the action of microwaves, the waste bamboo was semi-liquefied. Semi-liquefied bamboo (SLB) was dispersed in gelatin (G) solution, and then the solution was cross-linked and freeze-dried to obtain SLB-G aerogels. The prepared SLB-G aerogels possessed high porosity (93.6–95.7 %), low density (26.7–35.3 mg cm−3), low thermal conductivity (0.057–0.098 W m−1 K−1) and excellent sound absorption performance. The results show that SLB is a mixture of bamboo fibres as the key component, showing its compatibility with gelatin solution to produce SLB-G aerogels. Compared with gelatin aerogels alone, SLB-G aerogels have higher thermal stability and mechanical strength, which are important indicators of their application value. The successful development of these aerogels provides a new way to effectively treat bamboo and leather wastes.

Dust is a serious worldwide pollution, notably for nanoscale particles that are both toxic and difficult to control. Dust suppression can be done by adsorption on solid wastes, such as collagen from by-products of leather manufacturing. Here we review dust pollution and dust control, notably using collagen degradation products. Simulation experiments show that dust suppression using modified collagen degradation products reaches 68.2% for particulate matter 2.5 (PM2.5) and 78.7% for particulate matter 10 (PM10). The advantages and disadvantages of the current dust suppressors are discussed.

Noble hydrogel beads based on gelatin and oxidized corn starch were synthesized, and their usefulness and feasibility in treating effluent with dyes were studied in this work. Tartrazine was introduced as a model material. The kinetics of the tartrazine adsorption of the hydrogel beads were of a pseudo-second-order, and its adsorption isotherm is better fitted with the Langmuir model in comparison with the Freundlich model. With a pH of 2.5 coupled with a stirring speed of 400 r.p.m. and bath temperature of 35 °C, a maximum adsorption capacity of 293 mg g−1 was achieved. The hydrogel beads were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The results revealed that the blends have a uniform porous structure and can form stable Schiff base structures. The blend also had good stability and compatibility on mixing with electrolyte solutions, and swelling behavior measurements revealed that the hydrogel beads had excellent water-absorbing capacity. The adsorption approach is considered as the most effective method of removing dyes from effluents, which among new synthetic materials become high-profile as adsorbents in recent years. This work provides a noble synergistic hydrogel beads based on oxidized corn starch (OCS) and gelatin (G). The OCS and G can form three-dimensionally cross-linked networks owing to Schiff’s base formation. This work also proved that the form of hydrogel beads can be implemented in the synergistic materials for removing dyes from effluents, which has so far been neglected in the literature.

The NaOH/urea treatment of starch results in granular cold-water-soluble starch (GCWSS). The research indicated that the optimized condition for this treatment was aqueous solution of 14% w/v NaOH and 12% w/v urea (all dosages based on starch weight) at ambient temperature (25 °C) for 10 min with stirring. The aqueous solution was then treated a water-extraction and alcohol-precipitation method. The solid sample was dried in an oven at 60 °C. The GCWSS displayed a cold-water solubility of ~90%. The GCWSS had lower amylose content. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction also indicated that it was an amorphous solid with a V-type pattern (single-helix). The NaOH/urea solution could destroy the inter and intra hydrogen bonding of starch thereby decreasing glass transition temperature, and improve the cold water solubility of native starch.

Herein, a carboxylate-based deep eutectic solvent (DES) was used to dissolve gelatin and prevent its gelation effect. The sodium acetate trihydrate (SAT)/urea DES was successfully prepared and the formation mechanism was explored by FTIR. The effect of water dilution on microstructure and physicochemical properties of the DES was investigated by 1H NMR, viscosity, conductivity, and DSC. The results showed that the increase of conductivity, the reduction of viscosity and melting temperature were attributed to the addition of water. The water dilution caused the intensive H-bonding interactions of DES to weaken gradually and even disappear at around 50% w/w water addition. The “water-in-SAT/urea-DES” system was employed to dissolve gelatin and the interactions between gelatin and DES were explored by DLS. The solubility analysis displayed that DES30 W (SAT/urea with 30% w/w water content, based on DES weight) was an optimal dissolution system for gelatin, which could exhibit high solubility and overcome its gelation. The addition of water into DES can obviously reduce the phase transition temperature and the viscosity of gelatin-DES system by DSC and viscosity measurements. Moreover, the structure and molecular weight of gelatin didn’t change according to FTIR and GPC after regeneration. The study provides a novel system for gelatin dissolution that can significantly avoid its gelation, and the system will be more conductive to the application of gelatin in various fields.

With the expect to research the influential factors to heat transfer property of waterborne polyurethane(WPU), synthesis and membrane properties of WPU are researched, to which the composition of monomers, such as the 2,4-toluene diisocynate(TDI), isophorone diisocyanate (IPDI), polypropylene glycol(PPG with Mn = 1000, 2000 g/mol), dimethylol propionic acid(DMPA) and small molecular ethylene glycol(EG) are discussed. The orthogonal experiments show that the order to affect the thermal conductivity is PPG > DMPA > R(-NCO/-OH). The differences in thermal conductivity of WPU membrane samples are expressed, wherein through DMA, DSC, TG, FTIR, AFM, and XRD analyzed. A fact that thermal conductivity has a strong correlation with crystallization behavior of WPU membrane samples. The crystallization behavior is dependent upon the degree of microphases separation between hard segment and soft segment and that all attribute to the short range, long range and microcrystalline ordering, similarly which that create a well free paths for phonon conduction and accompanying with the enhancement of heat conducting properties of WPU membranes.

Oxidized Bacterial Cellulose (OBC)-hydroxyapatite (HAp)-gelatin (Gel) nanocomposites were prepared by a biomimetic process. HAp nanocrystals were precipitated in a mixed solution of Na2HPO4 (pH 9.2) and Gel solution at 37 °C, and OBC was used to generate a three-dimensional (3D) network stent. The tensile strength of OBC-HAp-G was higher than 0.3 MPa, and the complete degradation time was approximately 90 d in Simulated Body Fluid (SBF). Fourier transform infrared spectroscopy demonstrated that a coordinate bond had formed possibly between HAp and the cellulose hydroxyl. X-ray diffraction showed that both the oxidation of bacterial cellulose and an increase in Gel content induced the formation of tiny HAp crystallites during composite fabrication. Specific surface area and porosity measurements indicated that a low Gel concentration contributed to retention of porous structure. The Ca and P contents on the surface of materials increased initially and then decreased with an increase in Gel content, as measured by energy dispersive spectroscopy. From the thermogravimetric data, the increase in decomposition temperature suggested the formation of chemical bonds among OBC, HAp, and Gel. The above results suggest that the OBC-HAp-G0.3 composite is a potential bone scaffold material.

Degraded gelatin (Gel) and oxidized corn starch (OCS) as abundant, recyclable, and biodegradable materials can be applied to agricultural production, which has been investigated in this research. Firstly, the prepared oxidized corn starch-gelatin (OCS-Gel) composite material was characterized through a Fourier transform infrared spectrometer (FT-IR), a scanning electron microscope (SEM) picture, and a thermogravimetric analysis (TGA). The OCS-Gel was then used as a liquid film mulching for agricultural production, and the application performances (hygroscopicity, permeability, water retention, etc.) of the OCS-Gel were measured. Finally, the planting rapeseed experiments were carried out, and the germination and growing state of the rapeseed seeds were observed. The results from the structural analysis indicated that OCS-Gel enriches pore structure and exhibits high thermal stability up to 324.8 °C. In the application experiments, the OCS-Gel showed excellent properties of water-absorbing and water-retention and low permeability. In addition, the germination rate of the rapeseed seed reached 80 %, and the height of rapeseeds obviously increased in pot experiments after adding the liquid film mulching.

Herein, NaOH solution of a finite concentration was used to pretreat starch, which serves a novel effective pretreatment. A starch-based high-performance adsorptive hydrogel (STAH) was successfully prepared by grafting polyacrylic acid (PAA) onto starch and then crosslinking with N,N'-methylene-bisacrylamide (MBA). This adsorbent was employed to adsorb typical organic cationic dye contaminants (methylene blue (MB)) from high concentration effluents. The effect of the pretreatment time of starch on adsorption capacity of STAH was investigated in detail based on starch molecular weight, solid state 13C nuclear magnetic resonance spectra and grafting parameters. The results suggested that the optimal adsorbent (STAH20) presented the highest grafting parameters (50.06% reaction ratio of C6 in starch, 90.79% grafting efficiency, and 248.49% grafting ratio of PAA). STAH20 exhibited maximum adsorption capacity (2967.66 mg/g) in optimal conditions and excellent reusability after 4 rounds of recycling. The adsorption process of STAH20 for MB was consistent with the Langmuir model, obeyed the pseudo-first order model with intra-particle diffusion, and was endothermic and spontaneous. Using this pretreatment, the semi-crystalline structure of starch was destroyed, and numerous hydroxyl groups were gradually exposed with time, which is conducive to the graft reactions. The number of –COOH/ –COO– groups increased, which significantly enhances the hydrogen-bonding interaction and electrostatic interaction between STAH and MB and improves the adsorption capacity. Our study provides a method for low-energy, inexpensive, effective and simple starch pretreatment for the fabrication of STAH that exhibits significant potential for application in the removal of organic cationic dye contaminants.

The effective use of chrome leather scraps not only addresses the issue of properly disposing of leather waste but also can produce added-value products. In this paper, collagen hydrolysate (CH) from chrome leather scraps was modified by graft copolymerization using acrylic acid and acrylamide to synthesize grafted CH (GCH), and then for the first time used for retardation in Portland cement. FTIR analysis showed that the C O stretching vibration peak of GCH at 1685 cm−1 was obviously appeared compared with that of CH, which indicated that graft copolymerization between CH and the monomers successfully occurred. The GCH exhibited excellent stability and biodegradability. The addition of GCH efficiently postponed the setting process of the cement. The strength of the cement was closely linked to the dosage of GCH. The addition of 0.1% GCH improved the strength of the cement, but the addition of more than 0.1% GCH caused a decline in the strength. SEM observation showed that the crystal morphology of the cement significantly changed from needle-like to lumpy with the addition of GCH. Moreover, we also found that the hydration reaction of cement reactants (such as alite and belite) was inhibited and less hydration product (Ca(OH)2) was formed after the addition of grafted CH, thereby achieving the retarding effect. This paper indicated that GCH can be used as a novel and eco-friendly cement retarder, providing a path for maximizing the recycling of leather waste and achieving sustainable development in the leather industry.

Waterborne polyurethane (WPU) was successfully synthesized with two ways of one-step method and two-step method, mainly focusing on the effects of asynchronous synthesis method on WPU films’ structural features and thermal conductivity. Compared to the one-step synthesis method of WPU (OS-WPU), the two-step synthesis method of WPU (TS-WPU) showed a high thermal conductivity and approximately 1.4-fold higher than OS-WPU. In addition to this, the water- and solvent-resistance properties and crystallinity of TS-WPU also displayed a better performance than that of OS-WPU. Instrumental analyses of FTIR, DSC, DMA, AFM, SEM and XRD indicated that TS-WPU had an evenly phase separation and lots of microcrystal domains, which is owing to the more ordered structures existed in hard and soft segment domains. In short, the long-range order, short-range order and microcrystal domains existed in WPU can facilitate the phonon propagation, and that is corresponding to the increasing of thermal conductivity.

An efficient method was developed to prepare oxidized potato starch under the pasting point by Electro-Fenton system, in which a complex of sodium citrate and Fe2+ (SC-Fe2+) was used as catalyst, and H2O2 was used as oxidant. In the preparation process the oxidation degree of starch was controlled by the molar ratios of SC-Fe2+ and hydrogen peroxide. The structures and thermal properties of the prepared oxidized starch were characterized by FT-IR, XRD, SEM, DSC and DTG. The characterization results indicated that the obtained oxidized potato starch owned one grainy molecule structure, and displayed a high viscosity (not less than 63 Pa·s) by comparing to the raw starch. The carbonyl and carboxyl contents of oxidized potato starch achieved 0.81 per 100 AGU and 0.79 per 100 AGU, respectively after the raw starch was oxidized. And the oxidized starch showed good thermal stability, which can dramatically improve the application performance of starch-based biomaterials.

Degraded gelatin (Gel) and oxidized corn starch (OCS) as renewable and abundant recyclable and biodegradable materials can be applied to dust mitigation, which has been investigated in this research. Blends of oxidized corn starch and gelatin (OCS-Gel) were prepared by introducing the OCS into the Gel. Sodium carboxymethyl cellulose was used as a thickener and dispersant in the blends. The OCS-Gel blends were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis (TGA). The results revealed that the blends have a uniform porous structure and can form stable Schiff's base structures. The TGA and DTGA thermograms indicated high thermal stability up to 325 °C. Moreover, the blend had good stability and compatibility by mixing with an electrolyte solution, and the biodegradability and water-sorption measurements also revealed that the OCS-Gel had excellent hygroscopicity and degradability. The results of contact angle measurements between OCS-Gel solutions and dust showed that the blends have a satisfactory effect on dust wetting, and the results of light-transmittance tests revealed that the blends had a good effect on dust-removal ability. In addition, the dust particles can be evenly adsorbed on the surface of OCS-Gel when they were evenly dispersed on the surface of the OCS-Gel solution and can then form a film. The simulation experiment for flying dust in an enclosed area indoors indicated that the dust-suppression degree for particulate matter less than 2.5 micrometers (PM2.5) and less than 10 micrometers (PM10) in size can reach 68.2% and 78.7%, respectively. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44437.

Leather processing has been an important light industry in China, which has contributed a lot to economy. The recent environmental challenges caused tremendous pressure to leather manufacture. The conventional beam house processes employ a wide range of chemicals which result in more than 60% of the total pollution in leather processing (mainly based on COD, BOD, TS, SS, NH3–N). In this study, cleaner beam house processes were tested on cattle sofa leather to provide a clean environment. A control experiment was run parallel using conventional beam house processes. The results show that the de-hairing is complete through pelt histological microstructure, the extent of opening up of fibre bundles is very good, which is substantiated through chrome distribution analysis, scanning electron microscopic pictures of wet blue leathers and the analysis of contents of total proteins, polysaccharide and hydroxyproline in composite liquor, and the performance of the leathers is shown to be satisfied with the quality standard of sofa leather. The results from composite water analysis show that the cleaner processes enjoy in the reduction of emission water, chemical oxygen demand, total solids and ammonia-nitrogen loads by 46%, 93%, 58% and 54%, respectively, compared to the conventional processes. The total dry sludge from the clean processes is almost eliminated, and the composite cost is decreased by 10%.

The thermal stability of sheepskin collagen cross-linked with chrome sulfate and mimosa (MI)–oxazolidine (OZ), respectively, had been researched in this experiment. All samples’ shrinkage temperatures (T s) are determined by a special T s-testing-apparatus and denaturation temperatures (T d) are determined by the differential scanning calorimetry. The relations between the modified collagens containing moisture and their hydrothermal stability, T s or T d, were studied. The results show that the cross linking agents can enhance the thermal stability of modified collagen whose T s are 109.8 and 110.6 °C for collagen treated with chrome and MI–OZ, respectively. When the samples contain 25–71.9% moisture for chrome leather and 20–71.1% for leather treated with MI–OZ, the hydrothermal stability will decrease with the increase of moisture. It was found that the difference between T s and T d of collagen modified by chrome is more obvious than that of collagen modified with MI–OZ. And when the moisture of chrome leather exceeds 55%, T d cannot express thermal stability of modified collagen as a substitute for T s, and the moisture is 40% for leather tanned with MI–OZ.