Physical Morphology and Quantitative Characterization of Chemical Changes of Weathered PVC/Pine Composites

This study investigated weathering effects on polyvinyl chloride (PVC) based wood plastic composites (WPC), with a focus on the color and structure that is attributed to the material composition. It is directed towards quantifying the main chemical modifications, such as carbonyl and vinyl groups which are formed during weathering. These composites were subjected to three weathering regimes: exterior, accelerated xenon-arc, and accelerated UVA. The change in color was monitored using colorimetry. Fourier transform infrared spectroscopy was used to identify and quantify the chemical modifications (carbonyl formation and vinyl propagation) due to weathering. Additionally, scanning electron microscopy was employed to observe the physical morphological changes that occurred. The results showed that exterior and accelerated xenon-arc and UVA weathering regimes increased the degree of lightness, total color change, carbonyl concentration, and wood loss on the surfaces of the weathered composites. The increased carbonyl concentration during weathering implied that degradation had occurred by oxidation process. Also, oxidation and lignin (from the wood) degradation influenced the color (lightness) of PVC based WPC upon weathering.     

Environmentally Friendly Polyurethane Composites: Preparation, Characterization and Mechanical Properties

The waterborne polyurethane (PU) prepolymer was prepared based on isophorone diisocyanate (IPDI), polyester polyol (N220), dimethylol propionic acid (DMPA) and hydroxyethyl methyl acrylate (HEMA). The modified waterborne polyurethane–acrylate (PUA) emulsions were obtained with different proportions of acrylate (butyl acrylate and methyl methacrylate) and initiating agent by in situ dispersion technique. The structures and thermal properties of prepared PU and PUA were analyzed and characterized with FT-IR, UV–Vis spectroscopy and DSC. The PUA hybrid samples had lower glass transition temperature of hard segment and higher decomposition temperatures than PU sample. Performances of the emulsion and film were studied by means of apparent viscidity, particle size and polydispersity, surface tension and mechanical properties. The results indicated that the particle sizes of the PUA dispersions were larger than those of the pure PU and the solvent resistance, mechanical properties of PUA films was improved compare with the unmodified polyurethane film. The film had the biggest hardness and the least water absorption when the BA/MMA mass ratio 5:5 modified PU. The obtained PUA have great potential application such as coatings, leather finishing, adhesives, sealants, plastic coatings and wood finishes.     

Preparation, Characterization and Application of Leather Particulate-Polymer Composites (LPPCs)

The present study describes the preparation and characterization of leather particulate-polymer composites (LPPCs) from solid wastes (chrome shavings/buffing dusts) generated during leather manufacturing processes. Nitrile butadiene rubber (NBR), Styrene butadiene rubber (SBR) and neoprene rubber were the polymers used at different concentrations. Pretreatment of leather wastes with suitable alkaline reagents enhances the binding efficiency with polymers chosen and the high interfacial bonding prevailing reduces the chromium leaching. Mechanical properties of the resultant polymer composites showed good machinable and nailing properties. Addition of poly vinyl chloride (PVC) further enhances the above said properties. Scanning electron micrograph analyses implies complete blending of components in LPPCs. The composites exhibit good machinable and nailing properties and are easily transformed to shoe heel, shoe sole and shoe last.     

Preparation and Characterization of Polyhydroxyalkanoate Bioplastic-Based Green Renewable Composites from Rice Husk

The biodegradability, morphology, and mechanical properties of composite materials consisting of acrylic acid-grafted poly(hydroxyalkanoate) (PHA-g-AA) and rice husk (RH) were evaluated. Composites containing PHA-g-AA (PHA-g-AA/RH) exhibited noticeably superior mechanical properties compared with those of PHA/RH because of greater compatibility with RH. The dispersion of RH in the PHA-g-AA matrix was homogeneous because of ester formation and the consequent creation of branched and crosslinked macromolecules, between the carboxyl groups of PHA-g-AA and hydroxyl groups in RH. The water resistance of PHA-g-AA/RH was higher than that of PHA/RH, although the weight loss of composites buried in soil compost indicated that both were biodegradable, especially at high levels of RH substitution. After 60 days, the weight loss of the PHA-g-AA/RH (40 wt%) composite was greater than 90 %. PHA/RH exhibited a weight loss of approximately 4–8 wt% more than PHA-g-AA/RH. The PHA/RH and PHA-g-AA/RH composites were more biodegradable than pure PHA, which implies a strong connection between RH content and biodegradability.     

New Non-food-Based Composites of Acorn Nutlet and Polycaprolactone: Preparation and Characterization Evaluation

Two dissimilar renewable resource-based thermoplastic acorn nutlet (TPAN) materials were prepared via twin-screw extrusion with the aid of glycerol or monoethanolamine as plasticizers, and then two TPAN/polycaprolactone (PCL) composites with different plasticized systems were prepared. Mechanical test showed that glycerol-based composites had excellent tensile properties, and at a PCL content of 50 wt%, their tensile strength and elongation at break reached 14.4 MPa and 1,361 %, respectively. The micro-morphologic investigation of liquid-nitrogen brittle fracture surface indicated certain interface adhesion between glycerol-based thermoplastic acorn nutlet (GTPAN) and PCL. Dynamic mechanical thermal analysis , differential scanning calorimetry and thermogravimetric analysis demonstrated that the weight ratios of TPAN in composites significantly affected the crystallinity, glass transition temperature (T_g), melting temperature (T_m) and thermal stability of composites. Soil burial degradation analysis displayed that all composites had excellent biodegradability. These results demonstrated that GTPAN/PCL composites had superior mechanical and biodegradable properties, enough to partially replace the conventional thermoplastic plastics.     

利用矾泥制备铵明矾

采用酸熔法分离矾泥中的铝与硅,不仅克服了碱浸工艺脱硅的复杂过程和铝回收率低的不足,而且解决了酸浸工艺中产品纯度低和设备材质要求高等问题,通过试验确定了酸熔最佳工艺条件为：温度200℃,时间30min,酸铝比1.18,活性铝的回收率为96.69%,铵明矾的纯度在99.5%以上。     

酸渣制备无水硫酸钠

采用炼油厂酸渣经水稀释后,添加含钠化合物进行中和反应,制备无水Na_2SO_4.最佳工艺条件为:将酸渣用水稀释20倍,按n(Na_2CO_3):n(SO_4~(2-))=1.10或n(NaOH):n(SO_4~(2-))=1.20的比例加入Na_2CO_3,溶液或NaOH溶液,油水分离去除油相后蒸发、干燥,在650℃下灼烧后溶解、过滤、蒸发、结晶,得到Na_2SO_4产品.NaCO_3法可将酸渣中约78%的SO_4~(2-)转化到产品Na_2SO_4中;NaOH法可将酸渣中约66%的SO_4~(2-)转化到产品Na_2SO_4中.制备的无水Na_2SO_4产品均达到GB/T6009-2003<工业无水硫酸钠>二类标准.     

新型污泥脱水絮凝剂的研制

以累托石和虾蟹壳为主要原料,制备出一种新型污泥脱水絮凝剂。研究了该絮凝剂的制备工艺条件,探讨了该絮凝剂的絮凝机理。该絮凝剂的最佳配方为：天然有机高分子材料与改性累托石质量比1：6,将其配制成质量分数为1％的絮凝剂工作液,处理污泥的最佳加入量为1mL／L,最佳沉降时间为20min。与传统絮凝剂聚丙烯酰胺相比,污泥脱水率提高了5．47％,污泥沉降时间缩短了33．33％,吨污泥单耗絮凝剂成本下降了4％,且处理过程中的二次污染大幅度减小。     

Biodegradable Composites Containing Chicken Feathers as Matrix and Jute Fibers as Reinforcement

This research demonstrates that chicken feathers can be used as matrix to develop completely biodegradable composites with properties similar to that of composites having polypropylene (PP) as matrix. Feathers are ubiquitous and inexpensive but have limited industrial applications. Feathers have been preferably used for composite applications due to their low density and presence of hollow structures that facilitate sound absorption. However, previous approaches on using feathers for composites have used the whole feather or the feather fractions as reinforcement with synthetic polymers as matrix resulting in partially degradable composites. In addition, the hydrophilicity of the feathers and hydrophobicity of the synthetic matrix results in poor compatibility and therefore less than optimum properties. Although it has been shown that feathers can be made thermoplastic and suitable to develop films and other thermoplastics, there are no reports on using feathers as matrix for composites. In this research, chicken feathers were used as matrix and jute fibers as reinforcement to develop completely biodegradable composites. Tensile, flexural and acoustic properties of the feather-jute composites were compared to PP-jute composites. Utilizing feathers as matrix could enable us to develop low cost 100 % biodegradable composites containing feathers or other biopolymers as the reinforcement.     

污泥碳化制备活性炭

采用城市污水厂二沉池湿污泥为原料,添加活化剂直接活化制备污泥活性炭。实验结果表明,最优的制备条件:0.5mol/L的KOH为活化剂,浸泡时间为20h,碳化温度为600℃,升温速率为15℃/h,碳化时间为1h。在此条件下所制备的污泥活性炭吸附性能最好,孔体积为0.19cm3/g,比表面积为737.61m2/g,碘值为879.62mg/g,性能优于普通颗粒活性炭。采用最优条件下制备的污泥活性炭吸附处理电镀废水,总铬去除率为69.46%,铅去除率为78.88%,镍去除率为60.34%。     

Preparation and Properties of Starch/Nanosilicate Layer/Polycaprolactone Composites

Starch nanocomposites have been prepared using mineral clay. Montmorillonite, kaolin and a surface-modified montmorillonite by dimethyl (hydrogenated tallow alkyl) ammonium cation were used. Starch-g-PCL nanocomposites have been prepared with graft polymerization through in situ ring-opening polymerization of ε-caprolactone in the presence of starch, Sn(Oct)₂ (Tin(II) 2-ethyl hexanoate) as an initiator/catalyst and silicate layers. In fact, the related composites were prepared in solution method, bulk polymerization and in situ polymerization methods with introducing the mineral clay. The effect of kind of clay on d-spacing of silicate layers was investigated and the obtained nanocomposites were analyzed using X-ray diffraction. The obtained compounds were characterized by Fourier transform infrared (FT-IR). Morphology of the prepared nanocomposites was investigated using scanning electron microscopy and DSC enhanced the study of thermal behaviour of the prepared composite compounds.     

Biopolymers Based Green Composites: Mechanical, Thermal and Physico-chemical Characterization

Natural cellulosic fibers are one of the smartest materials for use as reinforcement in polymers possessing a number of applications. Keeping in mind the immense advantages of the natural fibers, in present work synthesis of natural cellulosic fibers reinforced polymer composites through compression molding technique have been reported. Scanning Electron microscopy (SEM), Thermo gravimetric/Differential thermal/Derivative Thermogravimetry (TGA/DTA/DTG), absorption in different solvents, moisture absorbance, water uptake and chemical resistance measurements were used as characterization techniques for evaluating the different behaviour of cellulosic natural fibers reinforced polymer composites. Effect of fiber loading on mechanical properties like tensile strength, flexural strength, compressive strength and wear resistances has also been determined. Reinforcing of the polymer matrix with natural fibers was done in the form of short fiber. Present work indicates that green composites can be successfully fabricated with useful mechanical properties. These composites may be used in secondary structural applications in automotive, housing etc.     

用煤矸石和鼓风炉淤泥制备聚硅酸铁铝混凝剂

研究了以煤矸石和鼓风炉淤泥为原料,在常压条件下制备高效混凝剂凝剂聚硅酸铁铝的方法,确定了合理的生产工艺和操作条件,用该混凝剂处理实际废水,并与聚合硫酸铁的处理效果进行比较,结果表明,出水COD和色度去除率均提高约30%,SS去除率提高约10%,同时探讨了该混凝剂处理废水的反应机理。     

Synthesis of Polyurethane and Characterization of its Composites Based on Alfa Cellulose Fibers

Polyurethane (PU) based on polycaprolactone (PCL) and 4,4′ diphenyl methylene diisocyanate (MDI) was synthesized using a two-step method. The PU obtained was then blended with various amounts of cellulose extracted from alfa stems to prepare composite materials. The influence of cellulose on the thermal and mechanical properties of different composites was demonstrated by means of several characterization techniques such as Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM)…     

Preparation and Characterization of Xylan Derivatives and Their Blends

Although hemicellulose is found widely in nature, it is currently under-utilized as a raw material for commercial applications. It would be desirable to find new uses for hemicellulose in order to add value to this agro-based material. A common type of hemicellulose is xylan, which is found in a number of wood species and in cotton. In this work we prepared cationic and anionic xylan derivatives and characterized them by ¹³C NMR, FT-IR, size exclusion chromatography (SEC), thermal analysis, and rheology. In particular, the ¹³C NMR spectra of carboxymethyl xylan (CMX) and quaternary ammonium-adducted xylan (QAX) were fully assigned with the help of samples with different degrees of substitution. SEC indicated that the beechwood xylan showed a bimodal molecular weight distribution, but with derivatization the distribution tended to become unimodal. Thermal analysis and rheology studies did not uncover any surprises; the solution of xylan and its derivatives exhibited mostly Newtonian behavior. The blends of CMX and QAX produced a precipitate at almost all ratios, indicating the formation of a polyelectrolyte complex. When cationic and anionic xylan samples were added together to paper, the paper dry strength increased. Thus, the combination of cationic/anionic xylan may be of interest in selected applications.     

Poly(vinyl alcohol-co-lactic acid)/Hydroxyapatite Composites: Synthesis and Characterization

There is a wide range of applications where calcium phosphate and hydroxyapatite (HA) are used as biomaterials, e.g. as synthetic bone grafts, coating on metal prostheses (like hip endoprostheses or dental implants) and drug carriers. In the study, the design and synthesis of composites based on poly(vinyl alcohol-co-lactic acid)/hydroxyapatite (PVA-co-LA/HA) with potential for biomedical applications, they are presented. The hydroxyapatite particles were surface-grafted with l(+)-lactic acid in the presence of manganese acetate as catalyst, resulting in modified hydroxyapatite (HA_m) with improved capacity of bonding, respectively for the preparation of the composite based on PVA-co-LA/HA_m. FT-IR spectra further confirmed the existence of PLA polymer on the surface of HA particles. In synthesis of PVA-co-LA copolymer the different molar ratios PVA/LA (2/1, 1/1, 1/2), toluene/water: 1/2 (as azeotrope solvent mixture) and manganese acetate as catalyst, were used. The composite materials were synthesized in situ with 10 wt% HA, and respectively HA_m (reported to PVA and lactic acid components). The composite materials were characterized by FTIR spectroscopy, thermal analyses (DSC, DTG), ¹H-NMR spectroscopy, particle size distribution and zeta potential.     

Process,Characterization and Biodegradability of Aliphatic Aromatic Polyester/Sisal Fiber Composites

The biodegradability, morphology, and mechanical properties of composite materials made of Poly(butylene adipate-co-terephthalate) (PBAT) and sisal fiber (SF) were evaluated. Composites containing acrylic acid-grafted PBAT (PBAT-g-AA/SF) exhibited noticeably superior mechanical properties due to greater compatibility between the two components. The dispersion of SF in the PBAT-g-AA matrix was highly homogeneous as a result of ester formation between the carboxyl groups of PBAT-g-AA and hydroxyl groups in SF and the consequent creation of branched and cross-linked macromolecules. Each composite was subjected to biodegradation tests in Rhizopus oryzae compost. Morphological observations indicated severe disruption of film structure after 60 days of incubation, and both the PBAT and the PBAT-g-AA/SF composite films were eventually completely degraded. Water resistance of PBAT-g-AA/SF was higher than that of PBAT/SF, although weight loss of composites buried in Rhizopus oryzae compost indicated that both were biodegradable, even at high levels of SF substitution. The PBAT-g-AA/SF films were more biodegradable than those made of PBAT, implying a strong connection between these characteristics and biodegradability.     

Preparation and Characterization of Three Different Derivatized Potato Starches

The use of native starch as a thermoplastic polymer is limited by its fragility and high water absorption. Due to the presence of several hydroxyl groups in its structure, water acts as a natural plasticizer of starch, modifying its properties. It is necessary to chemically modify starch molecules by replacing hydroxyl groups with other functional groups to reduce water absorption. Chemical modification of starch granules also alters its swelling and gelatinization behavior. In this contribution we describe the chemical modification of starch and its influence on its hydrophilicity and heat resistance. Acetic acid, maleic anhydride and octanoyl chloride were used as derivatizing reagents. The effectiveness of the treatments was evaluated by means of infrared spectroscopy. Different tests were conducted in order to evaluate the influence of the different chemical modifications on starch structure and properties. Results showed that the treatments effectively reduced starch moisture susceptibility, while substantially altering other properties such as amylose content, swelling power, solubility, and heat resistance. Finally, films were prepared from native and derivatized starch and their surface polarity was evaluated.