Water-Based Processing of Fiberboard of Acrylic Resin Composites Reinforced With Cellulose Wood Pulp and Cellulose Nanofibrils

Despite the great potential of cellulose wood pulp and cellulose nanofibrils as reinforcing filler in thermoplastics,its use is limited due to its tendency to form agglomerates and due to its high hydrophilic character.Here we describe fiberboard composites with high contents of wood pulp or cellulose nanofibrils,and a resin of poly(styrene-methyl-methacrylate-acrylic acid)used as water-based emulsion.Cellulose wood pulp and cellulose nanofibrils were used directly in the form of water suspensions.The method is based on the flocculation of the polymer emulsion followed by agglomeration of a mixture of the polymer emulsion and cellulose suspension,leading to the co-precipitation of the composite material,which can be easily separated from the water phase.Composites with acrylic polymer/cellulose fibers in the proportions of 75:25,50:50 and 25:75 wt%were prepared.Composites were characterized by scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),thermogravimetric analysis(TGA),dynamic mechanical analysis(DMA)and water absorption tests.SEM analysis revealed a very good dispersion of the fibers without evidence of agglomeration,which led to superior mechanical properties.These results showed the effectiveness of the methodology and the potential of cellulose wood pulp and CNF as reinforcement fillers in fiberboard composites and any other high fiber-content materials.

Treatment of pulpless coloured anterior tooth by bleaching the interior of pulp cavity and filling the cavity with composite

A method of treating pulpless coloured anterior tooth is presented.Most part ofthe coloured dentin of the labial crown was removed and the dental structure was bleachedwith 30% hydrogen peroxide for 5min.The pulp cavity was then filled with whitephoto-curing composite.The result of the treatment is quite satisfactory.With our treatment,the intact contour of the crown and the hardness and gloss of the enamel are preserved.SEM proved that the composite was tightly bound with the enamel of the medial wall of thepulp cavity,forming an entity with the tooth,thus guaranteeing the strength of the crown.

Mechanical and Rheological Properties of Bamboo Pulp Fiber Reinforced High Density Polyethylene Composites:Influence of Nano CaCO_(3)Treatment and Manufacturing Process with Different Pressure Ratings

In order to investigate the effect of the relative motion of nano CaCO_(3)reinforced bamboo pulp fiber(BPF)/HDPE composite components on the mechanical performance,a comparative study was performed.BPF was treated by nano CaCO_(3)blending(BM)and impregnation modification(IM)technology.The composites were produced using hot press(HPMP),extrusion(EMP)and injection molding process(IMP).The physical morphology of BPF was similar at different manufacturing processes.Compared to the samples manufactured by HPMP,a decrease in the(specific)flexural strength of BPF/HDPE composites and an increase in those of composites treated by nano CaCO_(3)manufactured by EMP and IMP were observed.The injection molded composites exhibited the best values in the(specific)impact strength,(specific)tensile properties.IM had a greater effect on the rheological behavior of the composites than BM,and nano CaCO_(3)treatment most effectively affected the performance of the extrusion molded composites.

A New Route for Preparation of β-TCP/ PLLA Composite

A new facile route for preparation of β-TCP/PLLA composites is reported in this letter. SEM images display that β-TCP particles with average diameter of 400 nm were well bonded and distributed within the pore walls of the PLLA scaffolds. The mixture of the novel complex and human dental pulp cells was transplanted subcutaneously into the dorsal surface of a nude mouse. Two months later histological examination showed that new collagen and new dentin formed. The results revealed that the new nano β-TCP/PLLA composite combined with human pulp cells could induce dentin formation offering a new way to dental tissue engineering.

Effect of incorporation of raphia palm fruit pulp powder on the physicochemical, functional and sensory properties of biscuits

Background:Raphia fruit pulp is a good source of phytochemicals and some micronutrients and is locally consumed as a snack.The aim of this study was to valorize raphia pulp in biscuits production by partially substituting wheat flour in different proportions with flour obtained from the pulp of the raphia fruit.Methods:Ripe raphia(Raphia hookeri)fruits were purchased from local farms,thoroughly washed and the pulps extracted using a stainless-steel knife.These pulps were dried at 60℃for 12 h and grounded into flour.Wheat flour was substituted with the raphia pulp flour(RF)in five different proportions(10,20,30,35,and 40%).The functional properties and nutrient profile of the raphia flour and the biscuits obtained from these composite flours were evaluated.Sensory evaluation of the biscuits was also carried out using a nine-point hedonic scale.Results:The RF has a high-water absorption capacity WAC(680%)and oil absorption capacity OAC(560%)favoring its use in pastry processes.The RF is rich in polyphenols 435.0±20(μg/100g),saponins(155±5 mg/100g)and potassium(922±20 mg/100g).The incorporation of the RF in biscuits significantly affect the chemical composition.The total polyphenols increased from 182±10μg/100g in the sample containing 10%of RF to 342±17μg/100g in the sample containing 40%of RF.Fibers increased from 8.75±0.03 mg/100g in the sample with 10%of RF to 10.08±0.27 mg/100g in the 40%substituted biscuit.Saponins increased from 69.9±0.01 mg/100g in the sample with 10%of RF to 90.22±0.01 mg/100g in the sample with 40%RF and potassium increased from 434.2±10 mg/100g in the sample with 10%of RF to 647.6±5 mg/100g in the sample with 40%of RF.Biscuit samples made with composite flour containing 20%of RF was the most accepted.Conclusion:RF can be used as a raw material to replace 20%of wheat flour in biscuit formulations and improve its nutritional and sensory properties.

甲基丙烯酸酐改性明胶/经处理牙本质基质生物活性支架的制备及性能

背景:牙髓-牙本质再生一直是近几年研究的热点及难点,构建复合生物支架材料为牙髓-牙本质再生提供了新的思路与方法。目的:观察甲基丙烯酸酐改性明胶/经处理牙本质基质支架对人牙髓干细胞增殖、迁移与成骨分化的影响。方法:将不同质量的经处理牙本质基质分散至甲基丙烯酸酐改性明胶溶液中,使甲基丙烯酸酐改性明胶与经处理牙本质基质的质量比分别为2∶1、1∶1、1∶2,采用冷冻干燥法制备甲基丙烯酸酐改性明胶/经处理牙本质基质支架,检测支架的微观形貌、吸水率及机械性能。采用不同质量比的支架浸提液、DMEM培养基(对照组)分别培养人牙髓干细胞,检测细胞增殖与迁移情况。采用不同质量比的支架浸提液+成骨诱导液、DMEM培养基+成骨诱导液(对照组)分别培养人牙髓干细胞,碱性磷酸酶染色分析成骨能力。结果与结论:①扫描电镜下可见3组支架均具有多孔结构,随着支架中经处理牙本质基质质量的增加,支架的孔隙率升高,组间两两比较差异有显著性意义(P<0.05);随着支架中经处理牙本质基质质量的增加,支架的吸水率升高,组间两两比较差异有显著性意义(P<0.05);随着支架中经处理牙本质基质质量的增加,支架的抗压强度、剪切强度增大。②CCK-8检测显示培养3,5,7 d,2∶1、1∶1、1∶2支架组细胞增殖吸光度值均高于对照组(P<0.05),并且随着支架中经处理牙本质基质质量的增加,细胞增殖吸光度值升高(P<0.05);细胞划痕实验显示2∶1、1∶1、1∶2支架组细胞迁移率均大于对照组(P<0.05),并且随着支架中经处理牙本质基质质量的增加,细胞迁移率增大(P<0.05)。③碱性磷酸酶染色显示,2∶1、1∶1、1∶2支架组细胞成骨分化能力均强于对照组,并且随着支架中经处理牙本质基质质量的增加,细胞成骨能力增强。④结果表明,甲基丙烯酸酐改性明胶与经处理牙本质基质质量比为1∶2的支架最适合牙髓干细胞的增殖与分化。

洛阳传统绿豆酸浆细菌群落组成分析和功能预测

为探究洛阳传统特色食品浆面条核心元素绿豆酸浆的细菌群落组成,利用Illumina MiSeq高通量测序技术对洛阳6家浆坊的绿豆酸浆进行细菌16S r DNA测序。结果表明:从6个绿豆酸浆样本中共鉴定出8个细菌门,涉及75个属和106个种;其中厚壁菌门为优势菌门(占比78.57~97.17%),乳杆菌属(占比20.95%~90.36%)和乳球菌属(占比3.26%~62.68%)为优势菌属,寡发酵乳杆菌、未分类乳球菌属是对应的优势菌种,而植物乳杆菌、弯曲乳杆菌、食木薯乳杆菌等是常见的次优势菌种;这些优势细菌均为乳酸菌,具有广泛益生作用。对绿豆酸浆中细菌群落进行功能预测,发现细菌群落的碳水化合物代谢和氨基酸代谢丰度高,特别是呈味氨基酸代谢通路和L-乳酸脱氢酶丰度均较高,推断绿豆酸浆独特的酸香味与细菌的氨基酸代谢以及乳酸合成有关。本研究结果为进一步研究绿豆酸浆发酵机理及开发相应发酵剂奠定了理论基础。

钙果复合果浆的功能成分及其减肥降脂作用

目的:枸杞、沙棘和钙果是我国北方特有的食药同源食物,为了深层次开发3种果实的营养成分,以钙果原浆(纯度100%)、沙棘原浆(纯度100%)、枸杞原浆(纯度100%)3种原料,按照体积比2∶1.5∶1调配混合,制成一款酸甜可口的钙果复合果浆,探究其功能成分及减肥作用。方法:采用电感耦合等离子体质谱法测定复合果浆的微量元素,采用高相液相色谱法测定维生素和类胡萝卜素,液相色谱-质谱联用法测定多酚类化合物和有机酸类化合物。建立肥胖小鼠模型,探究复合果浆对肥胖小鼠的减肥作用。结果表明,复合果浆富含多种功能成分,其中,钙含量为(73.671±4.918)μg/L,维生素B_(2)含量为(503.333±2.054)ng/mg,芦丁含量为(8.345±0.091)μg/mL。与模型组相比,剂量组经复合果浆干预后,小鼠体质量明显下降,甘油三酯含量显著降低(P<0.05)。结论:复合果浆对肥胖小鼠具有显著改善作用,本研究为钙果复合果浆的营养保健作用提供了数据支撑,并为预防肥胖提供了一种新的营养干预方法。

光交联复合水凝胶支架中人牙髓干细胞的成骨/成牙分化能力

背景:甲基丙烯酸酐改性明胶(gelatin-methacryloyl,Gel-MA)与经处理牙本质基质(treated dentin matrix,TDM)在一定比例下经过紫外线交联后形成的复合水凝胶支架具有良好的孔隙率、机械性能、溶胀性能及生物降解率,这为临床上年轻恒牙的牙髓再生提供了新的思路和方法。目的:探究1∶2质量比Gel-MA/TDM复合光交联水凝胶支架对人牙髓干细胞增殖能力及成骨/成牙本质分化能力的影响。方法:将第3代牙髓干细胞接种至1∶2质量比Gel-MA/TDM复合水凝胶支架中,采用CCK-8实验检测人牙髓干细胞在复合水凝胶支架中的增殖能力。将第3代牙髓干细胞接种至1∶2质量比Gel-MA/TDM复合水凝胶支架中并进行成骨诱导,采用碱性磷酸酶染色及茜素红染色观察矿化结节的形成情况,采用RT-PCR检测成牙相关因子(牙本质基质蛋白1、牙本质涎磷蛋白)和成骨相关因子(骨钙素、Runt相关转录因子2)的基因表达。结果与结论:①CCK-8检测结果显示,前7 d的牙髓干细胞增殖能力明显升高,第10天时速度减缓;②碱性磷酸酶染色及茜素红染色结果显示,Gel-MA/TDM复合水凝胶组牙髓干细胞的碱性磷酸酶活性及矿化结节生成强于单纯Gel-MA水凝胶组(P<0.05);③RT-PCR结果显示,Gel-MA/TDM复合水凝胶组牙髓干细胞中牙本质基质蛋白1、牙本质涎磷蛋白、骨钙素、Runt相关转录因子2的基因表达量明显高于单纯Gel-MA水凝胶组(P<0.05),且14 d基因表达量明显高于7 d(P<0.05)。结果表明,培养在1∶2 Gel-MA/TDM复合水凝胶支架上的牙髓干细胞表现出较好的增殖能力,能够强化牙髓干细胞的成骨、成牙本质分化能力。

Effect of Cellulose Microfibers from Sugar Beet Pulp By-product on the Reinforcement of HDPE Composites Prepared by Twin‐screw Extrusion and Injection Molding

The aims of this work turn towards the valorization of the underutilized Raw Sugar Beet Pulp by-product to produce white Cellulose Microfibers(CMFs),and its potential effect as a reinforcement for the development of High-Density Polyethylene(HDPE)composites.Pure CMFs were first obtained by subjecting raw SBP to alkali and bleaching treatments.Several characterization techniques were performed to confirm the successful removal of the amorphous compounds from the surface of individual fibers,including SEM,XRD,TGA,and FT-IR analysis.Various CMF loadings(5–10 wt%)were incorporated as bio-fillers into HDPE polymer to evaluate their reinforcing ability in comparison to raw and alkali-treated SBP using twin-screw extrusion followed by injection molding.Styrene–(Ethylene–Butene)–Styrene Three-Block Co-Polymer Grafted with Maleic Anhydride was used as a compatibilizer to improve the interfacial adhesion between fibers and the matrix.Thermal,mechanical,and rheological properties of the produced composite samples were investigated.It was found that the Young’s modulus were gradually increased with increasing of fibers loadings,with a maximum increase of 30%and 26%observed for composite containing 10 wt%of CMFs and raw SBP,respectively,over neat HDPE.While,the use of coupling agent enhances the ductile behavior of the composites.It was also found that all fiber improves the hardness and toughness behavior of all reinforced composites as well as the complex modulus particularly at 10 wt%.The thermal stability slightly increases with the addition of fibers.This study demonstrates a new route for the valorization of SBP by-products.These fibers can be considered as a valuable bio-fillers candidate for the development of composite materials with enhanced properties.

不同原料配比棉浆复合绝缘纸的制备与性能研究

为提高绝缘成型件、角环等湿法加工绝缘件的韧性及吸油性,加强其装配过程中的工艺可操作性,从而提升变压器的运行可靠性,对不同原料配比棉浆复合绝缘纸的性能进行研究,确定棉浆复合绝缘纸的棉浆比例,然后加工成成品并进行性能测试。结果表明:掺入棉浆体积分数为25%的棉浆复合绝缘纸综合性能最好,使用该原料配比制备的棉浆复合绝缘纸生产的角环、绝缘成型件具有较好的柔韧性及吸油性。

In vitro responses of human pulp cells and 3T3 mouse fibroblasts to six contemporary dental restoratives

In vitro responses of human primary pulp cells (HPCs) and 3T3 mouse fibroblasts to six contempo-rary commercial dental restoratives were evaluated using the WST-1 assay. The results show that Fuji II is not cytotoxic to both cells. Fuji II LC is not cyto-toxic to HPCs but cytotoxic to 3T3 cells, indicating that 3T3 cells are more vulnerable to 2-hydroxyethyl methacrylate (HEMA) than HPCs. Vitremer is very cytotoxic probably due to having diphenyliodonium chloride and HEMA in it. Z100 is very cytotoxic probably due to having triethylene glycol dimethacry-late (TEGDMA) in it. P60 is cytotoxic but less cyto-toxic than Z100 probably due to no TEGDMA in it. Durelon is the most cytotoxic among the six materials studied probably due to the high cytotoxicity of zinc ions. Additionally, the cytotoxcity of the tested mate-rials was found to be dose-dependent.

Effect of cooking conditions and oxygen-delignification on Bambusa tulda kraft pulping using experimental design and regression models

This study was concerned on the influence of cooking liquor parameters i.e. active alkali （AA） and sulfidity, on the properties of pulp produced from Thai bamboo by means of multivariate analysis. The investigated pulp properties were cooking yield and viscosity. The experiments were performed according to a face centered cube experimental design. Then, multiple linear regression （MLR） of independent and dependent variables were conducted with SPSS software using least square method. In order to optimize process, Pareto-Optimality method was employed. The obtained regression models were characterized by both descriptive and predictive ability （R^2 ≥ 95% and Rcv^2 ≥ 93%） and allowed the kraft pulping process with an acceptable viscosity （ 1110- 1 190 ml/g） and a total yield about 50% at a sulfidity level of 20-30% with 18% AA. Results indicated that high sulfidity at a lower AA could get high viscosity and relatively low kappa number for pulps. Also oxygen delignification was studied in this research.

RELATIVE IMPORTANCE OF WOOD DENSITY AND CARBOHYDRATE CONTENT ON PULPING YIELD AND PRODUCT QUALITY

SUMMARYThe purpose of this study was to evaluate basic density, chemical composition and fiber dimensions of ten Eucalyptus sp wood samples and verify the impact of this set of parameters and their combination on the Kraft pulping process yield and on bleached pulp quality. Ten eucalypt woods of different species, with basic densities varying from 365 to 544 kg/m3 and total wood carbohydrate contents varying from 70.0 to 74.5%, were transformed into kraft pulp of kappa number 17-18 and bleached to 90% ISO brightness by the sequence OD(PO)D. Wood basic density showed stronger correlations with fiber dimensions, pulping yield and pulp quality than did chemical composition. Lighter woods resulted in higher yields. However, wood specific consumption was lower for denser woods, even though these demanded more drastic pulping conditions to achieve a given kappa number. The pulp quality results suggest that lower density woods should be directed towards fabrication of refined paper (printing and writing grades) while the denser woods be directed to the sanitary papers segment (tissue grades).

二苯乙烯型荧光分子-水滑石复合光稳定剂的制备及性能

本研究利用共沉淀法将双三嗪二苯乙烯型荧光分子(FBs)插进水滑石(LDHs)层间,制备了一种高稳定性的荧光小分子插层LDHs复合光稳定剂(FBs-LDHs),评价其对高得率浆制备纸张的增白性能及光诱导返黄抑制作用。结果表明,LDHs可以有效地抑制FBs的光致异构现象,提高FBs-LDHs的荧光性能。48 h紫外老化后,FBs-LDHs涂布纸张的PC值较未涂布纸张低3.9,较FBs涂布纸张低3.0,说明FBs-LDHs能更好地抑制高得率浆纸张光致返黄。

赣脐4号脐橙果实挥发性组分分析

以‘赣脐4号’和‘纽荷尔’脐橙为试材,采用顶空固相微萃取及气-质联用技术对其果实中的香气成分提取并测定,结合主成分分析和聚类分析对主要贡献香气成分进行分类,结果表明:2个脐橙品种果实中共检测出76种香气成分,以烯烃类、醇类、醛类化合物为主,其中共有的香气成分有44种.果皮挥发性成分以烯烃类、醇类、醛类和酯类化合物为主,而果肉中还存在烷烃类和酮类物质.二者果实中挥发性物质的相对含量存在差异,其中含量最高的香气成分均为柠檬烯,‘赣脐4号’果皮含量达86.986%,为最高.主成分分析结果表明,‘赣脐4号’和‘纽荷尔’脐橙果皮中香气成分相似,但果肉中香气成分差别较大.其中‘赣脐4号’果肉具有23种特有香气组份,分别为4-蒈烯、肀-蒎烯、D-大根香叶烯、肀-蒎烯、罗勒烯、艾莫芬烯、马鞭烯醇、橙花叔醇、香芹醇、肀-榄香烯、月桂烯、杜松烯、异胡薄荷醇、L-异胡薄荷醇、叶绿醇、棕榈醛、L-紫苏醛、香柏酮、十四烷、十六烷、十一烷、乙酸香叶酯、对二甲苯;‘纽荷尔’果肉具有13种特有香气组份,分别为5-(1-甲基亚乙基)-1,3-环戊二烯、肀-水芹烯、肀-芹子烯、石竹烯、3,7,11-三甲基-1-十二烷醇、肀-萜品醇、青叶醛、柠檬醛、香芹酮、二十八烷、二十烷、乙酸芳樟酯、肀-乙酸松油酯;聚类分析与主成分分析结果一致.

高强高模聚乙烯纤维纸基复合材料的制备及性能

以高强高模聚乙烯(UHMWPE)短纤维和针叶木浆为原料,通过湿法成型技术结合树脂浸渍热压方法制备了UHMWPE纤维纸基复合材料,研究了原纸制备工艺和浸渍热压工艺对UHMWPE纤维纸基复合材料性能的影响。结果表明,当UHMWPE纤维与针叶木浆质量比为7∶3、针叶木浆打浆度为58°SR、酚醛树脂水溶液质量分数为10%、上胶量为44%、热压工艺为15 min、10 MPa、130℃时,制得的UHMWPE纤维纸基复合材料性能较好。当原纸经过浸渍热压后,所制备的UHMWPE纤维纸基复合材料抗张指数为59.11 N·m/g,与原纸相比抗张指数提高了6.9倍,表面变得更光滑,同时具有较低的介电常数(约1.97)、介质损耗因数(0.45×10^(–2))和较好的热稳定性。

利用中心复合响应曲面优化Fenton深度处理制浆中段废水

利用中心复合响应曲面分析对Fenton技术深度处理制浆中段废水进行了优化,该方法利用建模的方式打破了实验参数的设置范围,相较于传统的单因素和正交分析方法得到了更加符合实际的最优工艺参数,亚铁和过氧化氢与废水COD的质量比以及最佳p H分别为1∶0.6、1∶0.6和1∶4。在所确定的最佳条件下,CODCr去除率达到86%以上。本研究结论为Fenton氧化处理废水最佳条件的确定提供了一种更为准确的方法。

不同树龄日本落叶松的化学组成与制浆特性

对不同树龄日本落叶松的化学组成和硫酸盐法制浆特性进行研究与比较。结果表明:随着树龄的增大,原料中碳水化合物含量逐渐降低;冷水抽出物、热水抽出物和1%NaOH抽出物含量增加。碳水化合物组成中,随树龄增大,葡萄糖和木糖含量降低,半乳糖含量增加。通过对日本落叶松硫酸盐法制浆工艺参数的优化研究,确定最佳蒸煮条件为:用碱量(Na2O计)21%、硫化度25%、液比1∶4、最高温度170℃、保温时间2.5h。随着树龄的增大,蒸煮耗碱量增加,纸浆硬度增高。树龄较小的12年生日本落叶松纸浆的物理强度性能较好。综合对不同树龄日本落叶松化学组成和硫酸盐法制浆特性研究结果认为:12年生日本落叶松的硫酸盐法制浆性能优于树龄较大的日本落叶松,23年生日本落叶松的制浆性能相对较差。

小叶龙竹的化学成分与制浆性能

研究了小叶龙竹(Dendrocalamusbar batus)的化学成分、纤维形态、成浆性能,并与造纸工业目前使用较多纸浆树种慈竹(Bambusa affinis)、毛竹(Phyllostachys edulis)、云杉(Picea asperata)、马尾松(Pinus massoniana)、桉树(Eucalyptus globulus)等相比较。结果表明:小叶龙竹灰分、SiO2、冷水抽提物、热水抽提物、苯-醇抽提物、1%NaOH抽提物、木质素、戊聚糖、纤维素含量分别为1·82%、0·25%、2·99%、3·76%、1·65%、16·73%、28·13%、15·78%、51·00%;纤维平均长度为5·25mm、宽度为20·13μm、长宽比为260·80;小叶龙竹具有纤维平均长度较长、长宽比较高、纤维素含量较高、木质素含量较低的优势,其成浆容易,撕裂强度较高,是一种优良的竹类纤维原料。