Pulp Properties Research Articles

Wet End Chemical Properties of a New Kind of Fire-Resistant Paper Pulp Based on Ultralong Hydroxyapatite Nanowires.

In 2014, a new type of the fire-resistant paper based on ultralong hydroxyapatite (HAP) nanowires was reported by the author’s research group, which had superior properties and promising applications in various fields, such as high-temperature resistance, fire retardance, heat insulation, electrical insulation, energy, environmental protection, and biomedicine. The wet end chemical properties of the fire-resistant paper pulp are very important for papermaking and mechanical performance of the paper, which play a guiding role in the practical production of the fire-resistant paper. In this paper, the wet end chemical properties of a new kind of fire-resistant paper pulp based on ultralong HAP nanowires are studied for the first time by focusing on the wet end chemical parameters, the effects of these parameters on the properties such as flocculation, retention, draining, and white water circulation of the fire-resistant paper pulp, and their effects on the properties of the as-prepared fire-resistant paper. The experimental results indicated that the wet end chemical properties of the new kind of fire-resistant paper pulp based on ultralong HAP nanowires were unique and entirely different from those of the traditional paper pulp based on plant fibers. The wet end chemical properties of the fire-resistant paper pulp were significantly influenced by the inorganic adhesive and its content, which affected the runnability of the paper machine and the properties of the as-prepared fire-resistant paper. The flocculation properties of the fire-resistant paper pulp based on ultralong HAP nanowires were affected by the conductivity and Zeta potential. The addition of the inorganic adhesive in the fire-resistant paper pulp based on ultralong HAP nanowires could significantly increase the conductivity of the fire-resistant paper pulp, reduce the particle size of paper pulp floccules, and increase the tensile strength of the fire-resistant paper. In addition, the fire-resistant paper pulp based on ultralong HAP nanowires in the presence of inorganic adhesive exhibited excellent antibacterial performance. This work will contribute to and accelerate the commercialization process and applications of the new type of the fire-resistant paper based on ultralong HAP nanowires.

Development and evaluation of ready to serve (RTS) beverage from bael (Aegle marmelose Correa.)

A research study was carried out to develop a RTS beverage by exploiting the nutritional and organoleptic properties of bael fruit pulp. Six treatment combinationsof bael RTS with 10, 15 and 20% of pulp concentration and 10 and 15°B of TSS were prepared based on the review of literature. The biochemical and organoleptic properties of the prepared RTS were evaluated during storage. The pH, ascorbic acid and antioxidant activity of the RTS decreased with the storage, while acidity and total sugars increased. Results of the sensory evaluation showed that there was a significant difference between treatments in terms of color, flavor, taste, body and overall acceptability. From the results of quality assessments, the formulated bael RTS beverage with 15% pulp and 15°B TSS was found to be superior and suitable for consumption up to 12 weeks without any significant changes in the quality characteristics.

Elastic metamaterial composite made of molded pulp and steel for suppression of low-frequency vibration in thin-plate structures

This study proposes EMMs made of molded pulp and steel composite structures; molded pulp can be used to manufacture periodic shapes with low cost and environmental burden, which can help in the application of EMMs to steel structures that are widely used in engineering products. Toward this end, the frequency-dependent mechanical properties of the molded pulp are first identified via the vibration testing of pulp-steel laminate structures; the measured data confirm the high damping properties of molded pulp. Subsequently, wave propagation within the EMM is analyzed using the wave finite element method via dispersion curves, which suggest that the EMMs fabricated using molded pulp can attenuate wave propagation in wide frequency ranges by combining the effects of geometrical periodicity (i.e., band gap) and the material damping of the molded pulp. Further, the effects of geometrical parameters on band gaps are investigated; the results indicate that the proposed EMMs can open up band gaps in frequency ranges lower than 1000 Hz for thin plates used in engineering products. Finally, the frequency response functions of the EMMs are experimentally measured; the results confirm that EMMs can suppress vibrations in wide frequency ranges corresponding to the wave attenuation obtained by the dispersion analysis.

Desorption and thermophysical properties of feijoa pulp as affected by temperature and moisture content

ABSTRACT Feijoa has a high nutraceutical and agro-industrial potential, an attractive opportunity for Colombia to enter new markets with innovative products. However, there is little knowledge about its behavior and requirements for its proper industrial processing. The studies of thermophysical and sorption properties are fundamental for analyzing and optimizing the different unit operations, evaluation, and product quality control. This study aimed to determine and mathematically model the physical, thermal, and water desorption properties of feijoa pulp in the physiological ripening stage. The desorption isotherms were determined using the gravimetric method, based on saturated salts’ solutions to create atmospheres of controlled relative humidity (RH, %), in this case, at temperatures (T) of 8°C, 23°C, and 38°C and water activities (aw) between 0.07 and 0.98. From the isotherms model that best fits the experimental data, the isosteric heat of sorption (Qs ), differential entropy (ΔSdiff ), and Gibbs free energy (ΔG) were calculated. The density (ρ), thermal conductivity (k), and specific heat capacity (cp) properties were determined and modeled at different moisture contents (H: 75%, 80%, 85%, and 90%) in the temperature range (T) 20 to 80°C, using the pycnometer method, concentric cylinder method, and differential scanning spectrophotometry (DSC), respectively. The desorption isotherms of the feijoa pulp were type III with equilibrium moisture contents (Xe ) between 0.1246 and 5.5135 kg/kg (dry basis, d.b.), a monolayer moisture content of 0.2 kg/kg (d.b.); and spontaneity of the sorption phenomenon. Both cp and k depended more on H than on T; while ρ showed an equal relationship with both factors; these behaviors are characteristic of high humidity foods. The mathematical models obtained in this study are a valuable contribution for the food industry for an effective agro-industrialization, use, and added value of feijoa pulp through the design, control, and optimization of processes and equipment that involve the transfer of heat and matter.

An environment-benign approach of bamboo pulp bleaching using extracellular xylanase of strain Bacillus stratosphericus EB-11 isolated from elephant dung.

The use of microbial enzymes is highly encouraged in paper and pulp industries to reduce the excessive use of hazardous chemicals. During the study, xylanase of BacillusstratosphericusEB-11 was characterized for pulp bleaching applications. The extracellular xylanase was produced under submerged fermentation using bamboo wasteas a natural carbon source. There was fast cell division and enzyme production under optimized fermentation conditions in the bioreactor. The highest activity was 91,200Uafter30h of growth with Km and Vmax of 3.52mg/mL and 391.5μmol/min per mgrespectively. The purified enzyme with molecular mass ~ 60kDa had conferred positive activity on native PAGE. The strong inhibition by ethylenediaminetetraacetate and SDS showed the metallo-xylanase nature of the purified enzyme.The bacterial xylanase reduces the use of hydrogen peroxide by 0.4%. Similarly, biological oxygen demand and chemical oxygen demand were reduced by 42.6 and 35.2%. The xylanase-hydrogen peroxide combined treatment and conventional chlorine dioxide-alkaline (CDE1D1D2) bleaching showed almost similar improvement in physicochemical properties of bamboo pulp. Xylanase-peroxide bleaching reduces the lignin content to 4.95% from 13.32% unbleached pulp. This content after CDE1D1D2treatment was 4.21%. The kappa number decreased from 15.2 to 9.46 with increasing the burst factor (15.51),crystallinity index (60.25%), viscosity (20.1 cp), and brightness (65.4%). The overall finding will encourage the development of new cleaner methods of bleaching in the paper and pulp industry.

Nutritional Properties of Baobab Pulp from Different Angolan Origins.

The baobab tree (Adansonia digitata L.) is found widely in the forests and savannas of sub-Saharan Africa. The baobab fruit has a sour and slightly sweet taste and is widely consumed by the natives, thus containing a high nutritional value and providing a source of income for rural people. This study aimed to compare the nutritional composition of baobab fruit pulp from different localities in the Namibe province (Angola). Twenty samples of baobab pulp were collected in markets of the four municipalities of Namibe. The results obtained showed that there is some geographic location dependence on nutritional and functional composition. The municipality of Camucuio showed samples with higher fibre content (56.62 g/100 g) and vitamin C (288.9 mg/100 g). Samples from the Virei municipality stood out for their antioxidant activity (1936 mmol TE/100 g), high K content (42.4 mg/g) and higher values of protein (2.42 g/100 g). The samples collected in the municipality of Bibala stood out for their high contents of carbohydrates (28.1 g/100 g), total phenolic compounds (972 mg GAE/100 g) and Ca (3.80 mg/g). Despite the differences in origin, the high nutritional value of baobab fruit has the potential to improve the diet of thousands of people in Africa qualitatively.

Evaluation of the Physical Properties of Unbleached Kraft Pulp Produced from Persimmon Byproducts

This study examined the features of unbleached kraft pulp produced from persimmon byproducts (PB-UKP), which can be used to replace commercial kraft pulp. PB-UKPs prepared through the kraft pulping laboratory process were beaten to 500 and 400 mL CSF. Their fiber properties were subsequently analyzed and compared with those of commercial hardwood bleached kraft pulp (Hw-BKP). The physical properties of handsheets made from PB-UKP and Hw-BKP with a grammage of 60 g/m² were also evaluated.BRPB-UKP and Hw-BKP exhibited similar initial fiber properties. However, after beating, the fiber length of PB-UKP was longer than that of Hw-BKP, and the fines content of Hw-BKP increased considerably. Moreover, no noticeable difference was observed in the fiber width of the pulp. As the beating time increased, sheet bulk decreased, and the sheet strengths increased. The tensile and burst strengths of the handsheet made from PB-UKP were higher than those made from Hw-BKP at a similar sheet bulk because PB-UKP had a higher long fiber content. Thus, PB-UKP could be used as a colored raw material to manufacture paper products.

Influence of Wood Pulp Properties on the Efficiency of Carboxymethylation

Wood pulp properties are important controlling parameters to produce cellulose derivatives because they could affect the chemical accessibility and reactivity. This study investigated the effect of wood pulp properties on the carboxymethylation of pulp cellulose using various cooking techniques and species-appropriates fractionations. The efficiency of carboxymethylation was improved with the increase in the alpha-cellulose of pulp because lignin and hemicellulose, which adversely affect derivatization, were removed. In the case of hardwood, the removal of the fines comprising vessel elements had a positive effect on the carboxymethylation. In the case of softwood, the narrow variance of fiber length and width by fractionation was positive in improving the efficiency of carboxymethylation. The highest carboxyl content was 2.02 mmole/g when 12 g of monochloroacetic acid is added. Therefore, it is important to control pulp fiber characteristics to achieve the desired quality of carboxymethyl cellulose.

Differences in optical properties and internal qualities of ‘Fuji’ apple produced in different areas of the Loess Plateau region

Present studies have shown that near-infrared spectroscopy (NIRS) could be used to identify the producing area of apple. However, we still do not know whether the producing area affects the optical properties of apple, whether it affects the relationship between optical properties and internal qualities, and whether the optical parameters could be used to predict the apple-producing area. To answer these questions, the apples produced in three areas with different temperatures, precipitations, and altitudes in the Loess Plateau region, China, were used as samples to obtain the optical properties of apple pulp by a single integrating sphere system, analyze the differences in optical properties of apples produced in different areas, analyze the correlations between optical properties (absorption coefficient (μa) and reduced scattering coefficient (μs')) and internal quality indices (soluble solids content (SSC), moisture content and firmness), and investigate the feasibility of discriminating the apples produced in different areas and predicting the internal qualities using NIRS. The results showed that the apples produced in Luochuan had the highest SSC while Yangling apples had the highest moisture content. The μa had three absorption peaks at around 985, 1200, and 1430 nm, and the μs' of apples from three areas showed a similar trend with wavelength. The best correlation of μa with SSC and moisture content was found in Yangling apples with a correlation coefficient of −0.90 and 0.79, respectively. The built linear discriminant analysis based on μa spectra performed better in discriminating producing area. The established partial least squares regression models based on μa spectra had the best prediction performance for SSC and moisture content, while the model built with μs' had the best prediction performance for firmness. This study is helpful to understand the differences in optical property of ‘Fuji’ apple produced in different areas and offers information for identifying the producing area of fruit using NIRS technology.

Impact of residual extractives on the thermal stability of softwood Kraft pulp

Wood extractives are known to cause problems during the production of pulp and paper and to impact their mechanical properties. In the present work, we systematically explored whether minute residual amounts of extractives that reprecipitate on the fiber surface in the final stages of the pulping process would lower the thermal resilience of softwood Kraft pulp. Pulp samples subjected to different extraction methods were characterized by means of thermogravimetric analysis. The compound classes constituting the respective extracts were identified and quantified via gas chromatography-mass spectrometry/flame ionization detector (GC-MS/FID) and the influence of the individual compound classes on the thermal stability of the samples was investigated separately. Soxhlet extraction with an ethanol/toluene solvent system clearly led to increased thermal stability. Besides fatty acids and resin acids also sterols and sterol esters that do not carry carboxylic acid functionalities contributed to the deterioration of the thermal pulp properties. Lateral order indices derived from Fourier transformed infrared spectra and crystallinity indices derived from solid-state 13C nuclear magnetic resonance spectra indicate that upon thermal degradation, the presence of even minute amounts of extractives leads to an increased degree of supramolecular disorder. Moreover, the characterization of the samples’ carbohydrate composition by means of acidic hydrolysis showed a tendency towards facilitated pyrolysis of the hemicelluloses if extractives were present in the pulp.

Xylanase from thermotolerant Bacillus haynesii strain, synthesis, characterization, optimization using Box-Behnken Design, and biobleaching activity

AbstractThe economic value of xylanolytic enzymes is derived from their use in a variety of industrial processes, which necessitates a cost-effective manufacturing procedure. In the current study, forty bacterial isolates were isolated from water samples and investigate their efficacy to producing xylanase enzyme. The most potent bacterial isolate was identified by sequencing and amplifications of 16Sr RNA gene as Bacillus haynesii strain K6. The impacts of various culture conditions on the productivity of xylane were examined. Data showed that the highest xylanase production was achieved at pH 7, in presence of 3 g/L xylan, 5 g/L peptone, and incubated at 40 °C for 24 h. The Box-Behnken model was used to find the best parameters for the relevant variables, and the results revealed an increase in xylanase production with values of 35.02 U/mL. The maximum precipitation of xylanase from the optimized culture was attained by ammonium sulfate (60%) followed by purification using dialysis and sephadex G100 column chromatography. The purified xylanase had a 12-fold enrichment, with a specific activity of 84 U/mg and a molecular weight approximately 439 KDa determined by thin-layer chromatography (TLC)/mass spectrometry. The amino acid analysis of the purified xylanase enzyme revealed the presence of 15 amino acids, with the highest concentrations of 1940 and 1520 mg/L for proline and cysteine, respectively. Finally, the physical properties of wastepaper pulp were improved after treatment with xylanase enzyme. The whiteness and softness of xylanase-treated wastepaper were improved with percentages of 34.6% and 16.2%, respectively. Therefore, we recommend the use of xylanase enzyme in the bleaching process as it is a biologically synthetic material, safe, and suitable for industrial use, and it reduces the use of harmful chemicals.

Phytochemical Analysis of the Fruit Pulp Extracts from Annona crassiflora Mart. and Evaluation of Their Antioxidant and Antiproliferative Activities.

Annona crassiflora Mart., the marolo fruit of the Cerrado biome, is one of the most frequently consumed species from the Brazilian Midwest. This study aimed to evaluate the chemical composition and the antioxidant and cytotoxic properties of the fruit pulp of A. crassiflora collected at Chapada das Mesas, Maranhão, Brazil. The volatile concentrate was identified as mainly ethyl octanoate, ethyl hexanoate, and methyl octanoate. From the ethanol (LFP-E) and ethyl acetate (LFP-A) extracts were identified phenolic acids (p-coumaric, gallic, quinic, and ferulic), flavones and derivatives (apigenin, epicatechin, 2′-5-dimethoxyflavone, 3′,7-dimethoxy-3-hydroxyflavone, kaempferol-3-O-glucoside and 3-O-rutinoside, quercetin-3-O-glucoside, procyanidin B2, and rutin), aporphine alkaloids (xylopine, stephagine, and romucosine), and acetogenin (annonacin). For the LFP-E and LFP-A extracts, the total phenolic compound values were 15.89 and 33.16 mg GAE/g, the flavonoid compound content values were 2.53 and 70.55 mg QE/g, the DPPH radical scavenging activity showed EC50 values of 182.54 and 57.80 µg/mL, and the ABTS radical activity showed TEAC values of 94.66 and 192.61 µM TE/g. The LFP-E extract showed significant cytotoxicity and cell selectivity for the U251-glioma strain, presenting a GI50 value of 21.34 µg/mL, which is close to doxorubicin (11.68 µg/mL), the standard chemotherapeutic drug. The marolo fruit seems to be a promising source for developing innovative and healthy products for the food industry.

Investigation of the physicochemical properties of freeze-dried fruit pulp of Telfairia occidentalis and its potential use as suspending agent

Plant-based (natural) excipients can reduce the over reliance on synthetic ones. They have advantages such as low toxicity, biodegradability and low-cost relative to the synthetic ones. Telfairia occidentalis is a creeping plant that is cultivated for food in some African countries. The leaves, stem and root of the plant have been investigated as potential sources of medicine. This study aimed at evaluating the fruit pulp as a potential suspending agent. The ripe fruits of the plant were harvested and authenticated at the Department of Herbal Medicine, KNUST. The fruit pulp was extracted, freeze-dried and evaluated for its anti-microbial, phytochemical, physicochemical and anti-oxidant properties. Different concentrations of the dried pulp were used as a suspending agent in calamine lotion formulations, using bentonite as reference. The extract contained alkaloids, tannins, saponins, coumarins, glycosides, terpenoids magnesium and potassium. No antimicrobial and antioxidant activities were detected. The extract at all tested concentrations produced some level of suspendability. The test suspensions have good flow rates, high sedimentation volumes, high degree of flocculation, and relative ease of re-dispersion. However, these parameters were significantly (P < 0.05) lower (except flow rate) compared to those of bentonite as a suspending agent.

Improving Mechanical Strength and Water Barrier Properties of Pulp Molded Product by Wet-End Added Polyamide Epichlorohydrin/Cationic Starch.

As desirable food packaging materials, pulp molded products have attracted great attention from both academia and industry. To endow the products with high mechanical strength and water barrier properties by low-cost wet-end additives to broaden their application fields, polyamide epichlorohydrin (PAE) or/and cationic starch (CS) were added to the pulp slurry after the addition of oil- and water-proof agents. Results showed that the optimal pulp molded product was obtained at a PAE and CS content of 1.0 and 0.6%, respectively. The resulting product had a dry strength of 24.4 kN/m, a wet strength of 4.22 kN/m, and a water absorption of 51.5%. The addition of CS was beneficial to the properties of the PAE wet-end added product due to the formation of hydrogen bonding with cellulose fibers and PAE, which also led to a decreased PAE dosage for health concern as food packaging materials. Finally, the PAE/CS wet-end added pulp molded product was applied for orange fresh-keeping in the fridge. The product displayed much more shape stability and lower weight increase in comparison with that of the product without the addition of PAE and CS. This indicated the great application prospects of our designed pulp molded product as a fruit freprospectssh-keeping packaging material.

Comparison of Soda, Kraft, and DES Pulp Properties of European Black Poplar

Kraft pulping as the dominant pulping method contributes to several environmental problems. To overcome these problems, environmentally friendly pulping methods have been investigated. In the last years, deep eutectic solvents (DESs) have been identified as up-and-coming reagents in the lignocellulosic material processing and they are characterized as environmentally friendly. This study investigated the use of DES in pulp production from European black poplar chips. The DES mixture was prepared from choline chloride (ChCl) and ethylene glycol (EG). In addition, traditional soda and kraft pulping methods were carried out with poplar chips for comparison with the DES pulps. It was found that pulp production from poplar chips using DES was comparable to the soda and kraft pulps in terms of pulp yield, pulp viscosity, and opacity. The DES pulps easily reached target pulp freeness levels. However, the strength properties and brightness of the DES pulps were lower than those of the soda and kraft pulps. The strength properties of DES pulps can be improved with paper strength enhancers such as starch and micro or nanofibrillated cellulose. Also, the utilization of DES in pulp production may have an important role in cleaner production and it represents a greener alternative to traditional pulp production methods.

Among-family variations of direct measurement values for chemical and pulp properties in 4-year-old Eucalyptus camaldulensis half-sib families in Thailand

Abstract Amounts of wood chemical components (organic solvent extracts, Klason lignin, and holocellulose) and kraft pulp characteristics (yield and kappa number) were directly determined for 32 trees from eight half-sib Eucalyptus camaldulensis Dehnh. families in second generation of elite trees selected in Thailand. The mean values of all trees were 1.4 % for organic solvent extracts, 21.3 % for Klason lignin, 86.1 % for holocellulose, 44.4 % for kraft pulp yield, and 7.2 for kappa number, respectively. While repeatability values of growth traits and basic density were moderate to high (0.18 to 0.51), those in wood chemical components and kraft pulp characteristics showed quite low values (less than 0.10). No correlation coefficients were found between measured traits, except between stem diameter and tree height. Thus, it is concluded that selection of E. camaldulensis families with superior growth traits is suitable for production of raw material of pulp and paper in respect to quantity and quality of wood.

Physical properties of kraft pulp oxidized by hydrogen peroxide under mildly acidic conditions

Abstract The objective of this study is to gain further insight into the compositional and physical changes of kraft pulp caused by oxidation with hydrogen peroxide under acidic conditions. A softwood kraft pulp has been subjected to varying degrees of oxidation. Changes in the composition, as well as resulting physical properties of laboratory sheets were investigated. Findings indicated that the oxidation resulted in an increased carbonyl group content, a decrease in intrinsic viscosity and a change in hemicellulose composition. The oxidized pulps were found to have a reduced water retention value and a slightly reduced tensile strength (4–11 % at the investigated conditions). However, a substantial increase in wet web tensile strength (6–23 %) and wet tensile strength (134–242 %) of the sheets was obtained. The sheets could easily be repulped and an increased wet strength maintained to a large extent, even after recycling of the sheets.

High calcium content of Eucalyptus dunnii wood affects delignification and polysaccharide degradation in kraft pulping

Abstract Eucalyptus dunnii is cultivated in Uruguay for kraft pulping purposes. However, depending on the growth site, the kraft pulping properties of the wood vary highly, and in some cases, pulping is difficult. Different batches of wood were chemically characterized and the only significant difference related to the pulping properties was the calcium content. The calcium appears to at least partly be present in the form of crystals in the lumen. Kraft pulping experiments on wood with different calcium contents indicated that high calcium led to slower delignification, and higher yield losses. Hexeneuronic acid formation was not significantly affected. Possible mechanistic explanations for these effects are discussed.

Physicochemical Properties of Mango Pulp and Mid-infrared Characterization

Aim of the present study was to predict physicochemical parameters that are ash content, water content and fat content and to predict the presence of different organic molecule in the mango pulp. The prediction for the presence of the organic molecules has been done with the Fourier Transform Infrared Spectroscopy (FTIR). The spectra of mango pulp were measured using FTIR ranging from wavenumber 400 cm-1 to 4000 cm-1. Physicochemical parameters has been analysed with hot air oven, muffle furnace and automated Soxhlet apparatus for moisture content, ash content and crude fat content respectively. This study showed that FTIR spectroscopy has efficiency to distinguish some organic molecules present in the mango pulp.

Properties of Cellulose Pulp and Polyurethane Composite Films Fabricated with Curcumin by Using NMMO Ionic Liquid.

Cellulose pulp (CP), polyurethane (PU), and curcumin-based biocompatible composite films were prepared using a simple cost-effective method. Significant structural and microstructural changes were studied using FT-IR spectroscopy, XRD, and SEM. The 5% and 10% gravimetric losses of the CP/PU/curcumin composite were found to be in the range 87.2–182.3 °C and 166.7–249.8 °C, respectively. All the composites exhibited single Tg values in the range 147.4–154.2 °C. The tensile strength of CP was measured to be 93.2 MPa, which dropped to 14.1 MPa for the 1:0.5 CP/PU composite and then steadily increased to 30.5 MPa with further addition of PU. The elongation at the break of the composites decreased from 8.1 to 3.7% with the addition of PU. The addition of PU also improved the water vapor permeability (3.96 × 10−9 to 1.75 × 10−9 g m−1 s−1 Pa−1) and swelling ratio (285 to 202%) of the CP composite films. The CP/PU/curcumin composite exhibited good antioxidant activity and no cytotoxicity when tested on the HaCat cell line. The visual appearance and UV transmittance (86.2–32.9% at 600 nm) of the CP composite films were significantly altered by the incorporation of PU and curcumin. This study demonstrates that CP/PU/curcumin composites can be used for various packaging and biomedical applications.