橡胶胶料的自粘性

胶料的自粘性对成型加工和制品的产品质量起着重要作用。例如轮胎、自行车胎成型、夹布胶管成型及接头、硫化制品的结合面处容易裂开等均与自粘性有关。影响胶料自粘性因素很多:A.橡胶的特性;如天然胶的自粘性最好,使用天然胶时不存在自粘性这个问题,合成胶的自粘性不如天然胶。B.加工过程的温度、湿度胶料表面性质(老化。

扁齿胶皮和直式歪把底板、圆方底板的设计、性能及效果

一个时期以来,如何在以弧圈球为特征的技术发展形势下坚持和发展我国直板快攻打法,成了我国乒乓球界的重要研究课题。除在技、战术方面的探讨和实验外,球拍的革新逐渐被人们重视起来。本文将介绍由我设计、青岛球拍厂生产的扁齿胶皮、直式歪把底板、直式圆方底板的有关设计问题及其实际性能。

再生钙塑地板生产工艺可行性探讨

本文通过对原材料的选择和分析,基本配方的计算、设计和实际试验,再生胶料制备工艺流程和工艺条件的确定以及产品性能的测试等来探讨在配方中加入一定比例的废PVC生产再生钙塑地板的可行性。结果表明,尺寸为φ3 ×3的粒状废PVC与新PVC料的配比为50/50和25/75时能生产出较好性能的再生钙塑地板。与配方相适应的生产再生胶料的工艺条件为:高速捏和温度363±5K,时间5mim;密炼温度413±5K,时间3～5min,密炼中通过主机电流强度来控制塑化程度;开炼机辊筒温度393±5K,辊距3±0.5mm。所得产品的外观质量与纯PVC产品相当,拉伸强度4.0MPa,邵氏硬度96。文中还提出了配方中助剂需要量的计算公式及解决配制工艺中出现问题的方法。

Evaluation of rutting and low-temperature cracking resistancesof warm-mix recycled asphalt bindersunder the secondary aging condition

The rutting and low-temperature resistances of warm-mix recycled asphalt binders under the secondary aging condition were measured by the dynamic shear rheometer test and bending beam rheometer test.Effects of different types of warm-mix asphalt(WMA)technologies and additives were evaluated.Aging and improvement mechanisms were investigated by the Fourier transform infrared spectroscopy test.It is found that recycled binders after the secondary aging are more resistant to rutting and less resistant to low-temperature cracking.The two warm-mix asphalt technologies have opposite effects.Using the Sasobit WMA significantly improves the rutting resistance and reduces the low temperature resistance for the recycled binders due to its morphological change at different temperatures.The rutting factor values of recycled asphalt binders with the Sasobit additive increase by 4.6 to 5.6 times.However,using the Evotherm WMA causes the deterioration of the rutting resistance due to the structural lubrication effect.The rutting factor values of recycled asphalt binders with the Evotherm additive show the reduction of 52%to 62%.It is recommended to add the styrene butadiene rubber latex or crumb rubber powder into the warm-mix recycled asphalt binders to simultaneously improve the rutting and low-temperature cracking resistances.

高比例冷再生用水性环氧树脂基胶结料性能研究

沥青混合料冷再生是一种低碳环保的路面再生技术。为改善冷再生技术存在的低沥青混合料回收料(RAP)利用率、高胶结料用量的问题,设计了一种水性环氧树脂基胶结料,通过具有渗透能力的扩散组分实现RAP中老化沥青的有效利用。首先,基于分子动力学模拟和荧光显微镜分析了胶结料在老化沥青中的渗透扩散行为,验证了扩散组分对老化沥青的激活作用;其次,通过分子动力学模拟和附着力测试仪分析了胶结料与集料间的界面黏附,验证了胶结料的黏结能力;然后,借助差式扫描量热仪研究了胶结料的固化性能;最后,验证了低胶结料掺量下水性环氧树脂冷再生沥青混合料的路用性能。研究结果表明:扩散组分能够促进水性环氧树脂体系在老化沥青中的扩散,并且能够渗透到老化沥青中,提高冷再生条件下老化沥青的利用率;扩散组分的残留会影响水性环氧树脂体系与集料的黏附,但在掺量合理的前提下则有利于提升水性环氧树脂与老化沥青之间的黏结强度;扩散组分的掺加并不影响水性环氧树脂体系的固化效率,反而具有促进作用;掺加扩散组分后,水性环氧树脂基胶结料成型的高比例冷再生混合料具有较好的路用性能。

PVC gel bio-inspired adhesives with variable modulus and its application in a gripper

Inspired by the microstructure of gecko’s toe,two kinds of polyvinyl chloride(PVC)gels with different modulus were poured on a silicon mold with micropillars,and then a bio-inspired adhesive with variable modulus was manufactured in this study.The adhesions of variable modulus and fixed modulus bio-inspired adhesives were tested,respectively,on a smooth glass and a printed circuit board(PCB)with different surface structures.The results show that PVC gel bio-inspired adhesives with variable modulus have many advantages compared with the fixed modulus bioinspired adhesives.The adhesion of variable modulus bio-inspired adhesives on the rough PCB surface increased by 2−5 times,and due to the use of variable modulus of PVC gel,the surface micropillars can maintain high aspect ratio and flexible tips at the same time.Moreover,the use of PVC gel makes it easier to demold during the bio-inspired adhesives preparation.An adhesion-desorption device was made according to the movement of the gecko toes,and the PCB was successfully grasped.

Assessment of Sericin Biosorbent for Selective Dye Removal

The silk sericin is the main residue in silk production and it is found to be a low cost and efficient bio-sorbent. In this study, sericin was characterized with various techniques including SEM （scanning electron micro- scope）, XRD, N2 physisorption, FTIR （Fourier transformed infrared spectroscopy） and XPS （X-ray photoelectron spectroscopy）. The nitrogen content of sericin was ca. 8.5 mmol.g-1 according to elemental analysis. Dye adsorption by sericin biosorbent was investigated with the acid yellow （AY）, methylene blue （MB） and copper （II） phthalocyanine-3,4＇4＂4＇＂-tetrasulfonic acid （CuPc） dyes from water. Sericin displayed large capacity for AY andCuPc adsorption with adsorption capacities of respectively 3.1 and 0.35 mmol.g-1, but it did not adsorbed methyl- ene blue dye. This selectivity is due to the basicity of amide groups in seriein biosorbents.

Bio-reduction of Sulphur Dyes with Alkaline Pectinase

Sulphur dyes are invariably applied on cotton to produce deep shades at cheaper cost possessing all-round fastness properties except against chlorine. Being water insoluble, these dyes are reduced and solubilised with sodium sulphide at boil to develop affinity for cotton. Application of sulphide has generated global debate because of its eco-unfriendly technology of dyeing. In this work, attempts were made to substitute sodium sulphide with alkaline pectinase. Obtained results suggested the ability of the latter to cause effective reduction and solubilisation of sulphur dyes. Stability of reduction baths as well as colour fastness was also reported to be in line with those obtained using sodium sulphide.

Significant broadband extinction abilities of bioaerosols

Bioaerosol, an important constituent of the atmosphere, can directly affect light radiation characteristics due to absorption and scattering effects. Current research lacks a reasonable explanation for the extinction abilities of bioaerosols in a broadband. Herein, we measured the reflectance spectra of 12 com m on biomaterials and calculated their complex refractive indexes. The peaks of the imaginary part of the complex refractive indexes are located at wavelengths of approximately 0.7, 2.7, 6.1 and 9.5μm. Based on photographs of the floating structures of bioaerosols, we constructed a model for calculating the extinction abilities of bioaerosols in the wavelength range of 240 nm to 14 (im. Taking AN02 spores as an example, absorption was found to account for more than 90% of the total extinction. In addition, the theoretical calculations and experimental data of transmittance corresponding to the smoke box show that bioaerosol exhibits significant broadband extinction ability from UV to IR bands, which provides new directions for the development of broadband light attenuation materials.

Mineralization regulation and biological influence of bioactive glass-collagen-phosphatidylserine composite scaffolds

Biomimetic scaffolds are appealing products for the repair of bone defects using tissue engineering strategies.In the present study,novel biomimetic composite scaffolds,with similar properties to natural bone,were prepared,blended and cross-linked with bioactive glass,type I collagen and phosphatidylserine.When exposed to cell culture solution in the absence of a cellular source,the composite scaffolds form crystals with octahedral structure.These crystals are similar to the products derived from MC3T3-E1 cell mineralization within the composite scaffolds,with respect to both composition and morphology.Furthermore,crystals with octahedral structure were observed to develop into plate-like hydroxyapatite.The bio-mineralization behavior of the composite scaffolds is likely influenced by inorganic components.Finally,a rabbit tibia defect model shows that the highly bioactive properties of the investigated composites result in excellent bone repair.

Double network hydrogel with high mechanical strength:Performance,progress and future perspective

With high water content(～90 wt%) and significantly improved mechanical strength(～MPa),double network(DN) hydrogels have emerged as promising biomaterials with widespread applications in biomedicine.In recent years,DN hydrogels with extremely high mechanical strength have achieved great advance,and scientists have designed a series of natural and biomimetic DN hydrogels with novel functions including low friction,low wear,mechanical anisotropy and cell compatibility.These advances have also led to new design of biocompatible DN hydrogels for regeneration of tissues such as cartilage.In this paper,we reviewed the strategies of designing high-strength DN hydrogel and analyzed the factors that affect DN hydrogel properties.We also discussed the challenges and future development of the DN hydrogel in view of its potential as biomaterials for their biomedical applications.

Effect of treatment process on consolidation efficiency of fugitive dust cemented by bio-activated cementitious material based on CO2 capture

As a new green and environmental material, bio-activated cementitious material is attracting extensive attention. This study confirmed that the bio-activated cementitious material could mineralize and cement fugitive dust into the cal- cite-consolidation-layer based on CO2 capture and utilization. The results illustrated that treatment processes （non-pressure spraying, pressure spraying, non-pressure blending and pressure blending） had a strong effect on the microstructure and prop- erties of calcite-consolidation-layer. According to the analysis of X-ray diffraction （XRD） and Fourier transform infrared （FTIR）, calcite was prepared by bio-activated cementitious material during the cementation process. Meanwhile, scanning electron microscopy （SEM） and thermogravimetric-differenfial scanning calorimetry （TG-DSC） were adopted to measure the corresponding variation of porous characteristics and calcite content caused by different treatment processes. The results indi- cated that the microstructure of calcite-consolidation-layer from the spraying process had lower porosity and higher content of calcite than from blending processes. In addition, the mechanical properties of calcite-consolidation-layer were also tested. The hardness and compressive strength, which reached 19.5 GPa and 0.6 MPa, respectively, of calcite-consolidation-layer from the pressure spraying process were higher than those from the other three treatment processes. Compared with the non-treatment process, the four treatment processes had superior wind erosion resistance. Under the wind speed of 12 m/s, the mass loss of calcite-consolidation-layer from the pressure spraying process decreased from 2150.2 to 23.8 g/（m^2 h）.

Surface patterning and modification of polyurethane biomaterials using silsesquioxane-gelatin additives for improved endothelial affinity

Polyurethanes(PUs) are well-known for their biocompatibility but their intrinsic inert property hampers cell-matrix interactions. Surface modifications are thus necessary to widen their use for biomedical applications. In this work, surface modifications of PU were achieved first by incorporating polyhedral oligomeric silsesquioxane(POSS), followed by alteration of the surface topography via the breath figures method. Subsequently, surface chemistry was also modified by immobilization of gelatin molecules through grafting, for the enhancement of the surface cytocompatibility. Scanning electron microscopy(SEM) was used to verify the formation of highly ordered microstructures while static contact angle, FTIR and XPS confirmed the successful grafting of gelatin molecules onto the surfaces. In vitro culture of human umbilical vein endothelial cells(HUVECs) revealed that endothelial cell adhesion and proliferation were significantly enhanced on the gelatin-modified surfaces, as shown by live/dead staining and WST-1 proliferation assay. The results indicated that the combination of the strategies yielded an interface that improves cell attachment and subsequent growth. This enhancement is important for the development of higher quality biomedical implants such as vascular grafts.