Volume 7 Issue 3

Waxy maize contains nearly 100% of the branched amylopectin type of starch, which has a similar structure to that of a commercial anionic organic micro-particle (OMP). It was found that the maize starch would have the same function as the OMP if carboxymethyl groups were introduced; moreover, the performance of carboxymethyl starch as a retention and drainage aid could be enhanced by grafting some cationic groups on the backbone of the starch so that it could absorb on fibers through electrostatic attraction. In this study, the introduced groups of cationic-modified carboxymethyl starch (CCMS) prepared from waxy maize were determined by FT-IR and ¹H NMR spectroscopy. Factors affecting retention and drainage, comparison between CCMS and OMP systems, and also the strengthening effect of CCMS were studied. The results showed that CCMS had excellent performance when it was used with cationic polyacrylamide (CPAM) as a retention system. Compared with the OMP, CCMS had better retention performance when the dosage was in the range from 0.01% to 0.08%, and it yielded much more uniform formation of the handsheets. Additionally, CCMS had a strengthening effect on the paper, which distinguished it from other retention aids.

In this work, nanofibrillated cellulose (NFC) has been evaluated as a potential reinforcement for cement mortar composites. Two types of vegetable fibres with different composition and properties (cellulose content and microfibrillar angle), sisal, and cotton linters pulps, were initially characterised in order to assess their reinforcing capability. Sisal pulp was found to be most suitable as reinforcement for the brittle cementitious matrix. Nanofibrillated cellulose was produced by the application of a high intensity refining process of the sisal pulp. It was found that 6 hours of refining time was required to obtain the desired nanofibrillation of the fibers. Cement mortar composites reinforced with both the sisal fibres and the nanofibrillated cellulose were prepared, and the mechanical properties were determined under flexural tests. The cement mortar composites reinforced with the nanofibrillated cellulose exhibited enhanced flexural properties, but lower values of fracture energy, than the ones reinforced with the conventional sisal fibres.

Internal addition of fluorochemical greaseproof agent was applied to furnishes of different fibers, filler, binder types, and loadings to examine their effects under different degrees of refining on the greaseproof indicators such as air resistance, water absorption, and the Kit values of the resulting handsheets. The results showed that more refining tended to produce a tighter textured paper which was more suitable for the greaseproof purpose. The Kit values of the resulting handsheets were found to correlate with a polynomial regression equation of the Gurley air resistance (A) of the paper with an equation of Kit no. = 2.51 + 0.064 A – 0.002 A2. The results also showed that furnishes that blended northern softwood and Eucalyptus pulps at ratios from 25:75 to 75:25, depending on the strength requirements, had the best greaseproof performance. Among the fillers, sericite was superior to bentonite and PCC for contributing to greaseproof properties. However, filler loading exceeding 6.1% was undesirable. Soluble starch and polyvinyl alcohol were suitable binders for making greaseproof papers. Their dosages should be kept between 0.4 to 1.6%.

Simarouba versicolor wood was evaluated relative to its kraft pulping ability and compared with Eucalyptus urograndis wood. Comprehensive chemical analysis of wood and milled wood lignin (MWL) was performed, aiming to correlate wood and lignin structural features with kraft pulping response. Wood characterization of S. versicolor revealed higher lignin content (37.3%) and lower cellulose content (45.1%) than E. urograndis. 13C NMR spectroscopy was performed to characterize MWL, and the results showed a lower syringyl to guaiacyl ratio (S/G), higher degree of condensation, and lower β-O-4 linkages for S. versicolor. The gross heating value of S. versicolor was slightly higher than that for E. urograndis. Significant variations were observed in chemical charge demand and in pulping yield for the two species. This behavior was attributed mainly to the S/G ratio and degree of condensation of the lignin, although total and insoluble lignin, as well as cellulose contents may have affected pulping efficiency too.

Different substrate characteristic analyses have been studied on rice and triticale straw pretreated with NMMO (N-methylmorpholine-N-oxide) prior to biogas production. Simons’ stain, water retention value (WRV), and enzymatic adsorption were used to measure the change in the accessible surface area of the lignocellulosic substrates. FTIR was used to measure the change in cellulosic crystallinity and Time-of-Flight-Secondary-Ion-Spectroscopy (ToF-SIMS) to measure the ratio of cellulose to lignin on the sample surface. All methods showed increased accessible surface area and a decrease in crystallinity after the pretreatments. These qualities were linked to improved biogas production. In the future, the tested methods could replace the time-consuming methane potential analysis to predict the methane production of lignocellulosic materials. Simons’ stain, enzymatic adsorption, and crystallinity measurement by FTIR can be regarded as the recommended methods for the prediction of the improved biogas production as a result of the pretreatment.

In this work, laccase biosynthesis of two microorganisms, Trametes versicolor TISTR 3224 and Bacillus sp. TISTR 908 isolated in Thailand, was investigated using sugarcane bagasse (SCB) as substrate. Two-stage biological/physico-chemical pretreatment of SCB on delignification and saccharification yield was studied. A two-level full factorial design was applied and 3 factors influencing delignification and saccharification processes of SCB were studied including C:N ratio (10:1 to 20:1), temperature (100 to 140°C), and alkali concentration (0 to 5% w/w NaOH). It was found that during biological pretreatment of SCB, a greater amount of laccase was produced from T. versicolor in the early stage of growth compared with Bacillus sp. Nitrogen supplement enhanced laccase biosynthesis of T. versicolor. By contrast, Bacillus sp. required a smaller amount of nitrogen source to produce laccase. Biological treated bagasse was subsequently subjected to a physico-chemical treatment. The results showed that the highest xylose and glucose yield of 51.97% w/w based on carbohydrate content was obtained from T. versicolor cultivation at a C:N ratio of 20:1, and consecutively treated in 5% w/w NaOH solution at 140°C for 1 h. Bacterial/alkali and alkali pretreatment yielded xylose and glucose in smaller degrees compared with fungal/alkali pretreatment. T. versicolor preferentially degraded lignin in sugarcane bagasse relative to cellulose and hemicelluloses constituents, while Bacillus sp. simultaneously attacked both lignin and carbohydrate moieties, as indicated by analysis of relative FT-IR intensities ratios of pretreated and untreated sugarcane bagasse.

High-yield pulp (HYP) such as bleached chemi-thermo-mechanical pulp (BCTMP) from aspen wood, is now being used in the production of high-quality fine papers, and this is particularly true in China. In this study, the effect of using cationic polymers such as poly-aluminum chloride (PAC), polyethylenimine (PEI), cationic polyacrylamide (CPAM), and poly-(diallyldimethylammonium chloride) (PDADMAC) on Alkenyl Succinic Anhydride (ASA) sizing efficiency in HYP-containing pulp furnish was investigated. The results showed that the addition of only ASA emulsion to the HYP-containing furnish, without any cationic additives, did not yield an appreciable degree of sizing in the paper sheet. PAC (or alum) could improve the ASA sizing efficiency. PEI, PDADMAC, CPAM, and NaHCO3 all improved ASA sizing efficiency in the presence of PAC. The charge density of PEI was important for improving the ASA sizing performance. Also, the sequence of adding the cationic polymer affected the ASA sizing performance.

Cellulosic fibres provide a very agreeable environment for growth of bacteria due to large surfaces with high moisture absorbability. Therefore, the demand for an anti-microbial finish as an effective means of preventing disease transmission is high; it inhibits growth of or kills microorganisms on textile fabrics. This paper reports results of experiments where silver oxide (Ag2O) or zinc oxide (ZnO) was used as a catalyst with the halogenated phenoxy compound (Microfresh, MF) and a binder (Microban, MB) on cotton fabrics to improve treatment effectiveness and minimize its side effects. Anti-microbial-treated fabrics showed some new characteristic peaks in chemical structure as evaluated by Fourier Transform Infrared Spectroscopy. In an anti-microbial test, it was found that anti-bacterial activity increased as MF-MB chemical agents were applied to the fabrics. A noticeable result was that the metal oxide catalyst had a significant effect on enhancing the performance. Surface morphology of anti-microbial-treated cotton specimens showed roughened and wrinkled fabric surface with high deposition of the finishing agent, which had a lower breaking load and tearing strength resulting from side effects of the acidic treatment. However, the addition of the Ag2O catalyst was able to compensate for the reduction in tensile and tearing strength, and it is considered harmless for human skin.

SO4^2-/ZrO2-TiO2 catalysts prepared by precipitation and impregnation methods were employed for glucose conversion. The basic structures of the prepared catalysts were characterized by XRD, BET, NH3-TPD, XPS, and TEM techniques. The essential properties of SO4^2-/ZrO2 could be improved greatly by adding a suitable amount of TiO2. High BET area and pore volume favored glucose conversion. The conversion rate of glucose into levulinic acid catalyzed by SO4^2-/ZrO2-TiO2 increased significantly in an extremely low acid system, indicating that the acidic condition was favorable for levulinic acid formation. The combined yield of 5-hydroxymethylfurfural and levulinic acid reached 28.8% with the presence of SO4^2-/ZrO2-TiO2 when the Zr-Ti molar ratio was 5:5 at 170°C for 2 h in the extremely low acid system. Studies on catalyst recycling were also further investigated in this study.

This article investigates the effect of natural weathering on mechanical and morphological properties of rattan powder-filled natural rubber (NR) composites as a function of filler loading and silane coupling agent. The rattan powder samples in the range of 0 to 30 phr were compounded with NR using a laboratory size two-roll mill. The natural weathering test was carried out for six months. The degradation of the samples was evaluated by performing a tensile test, a Fourier transform infrared spectroscopy (FTIR), and a scanning electron microscopy (SEM) test. The results indicated that after natural weathering, an increase in stress at 100% elongation (M100) can be seen for samples without the silane coupling agent, whilst M100 was reduced for samples with silane coupling agent. A drastic reduction in tensile strength and elongation at break were observed for all samples due to the photo-oxidation process that occurred during the degradation of the samples. The extent of degradation on the samples’ surfaces and the presence of oxygenated products were confirmed by SEM and FTIR studies, respectively.