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This work assesses six different agricultural residues with the aim of finding alternative raw materials for a soda semichemical pulping process: stems of bell and chili pepper ( Capsicum annuum ), broad bean ( Vicia faba ), asparagus ( Asparagus officinalis ), pea ( Pisum sativum ), and okra ( Abelmoschus esculentus ). Pulping yields higher than 60% (m/m) were obtained, except for pea stems (43%). The drainability of all the pulps, expressed as the Schopper-Riegler index (ºSR), had values of over 70 ºSR. The Kajaani analyses of the fibers showed acceptable fiber lengths in all cases (0.64–0.92 mm), but on average shorter than the lengths of pulps from a commercial fluting paper (Old corrugated Container, OCC), that was found to be 1.27 mm. Handsheets of paper were produced both with the pulps under study and with mixtures of these pulps with OCC pulp. Several properties were measured to assess the use of the new fibers in a paper for cardboard production. The property showing the greatest differences was the Gurley porosity, ranging from 25 mL/min (asparagus) to 1300 mL/min (broad bean). Of the six residues tested, the okra residue fiber showed better properties than the commercial paper fiber (Concora Medium Test indexes: 1.5 N m 2 /g and 1.1 N m 2 /g respectively, Burst Indexes: 2.3 kPa m 2 /g and 1.7 kPa m 2 /g, respectively), yielding similar mechanical properties to those of high quality fibers obtained from miscanthus ( Miscanthus giganteus ). Broad bean residue could also be a promising raw material, though its properties are not as good as okra’s. [ABSTRACT FROM AUTHOR]

In order to identify faster-growing non-woody species usable for biomass and paper production, four Leucaena species (L. diversifolia, L. colinsii, L. salvadorensis and three varieties of L. leucocephala) were tested. All the Leucaena species showed a good soil and climatic adaptation to Spain Southwest except for L. salvadorensis. Studied Leucaena species showed biomass productivity ranges from 67.14 to 9.44tha−1 (o.d.b.) and 43.6 to 11.4tha−1 under Mediterranean conditions for the first and second year sprouts, respectively. The quantity of solubles and extractives shows similar values when compared with wood materials. Relatively lower lignin content in Leucaena (from 15.7% to 21.4%) species has been found with respect to other vegetal species. The α-cellulose contents (39.4–45.3%) are in the range of the normal values expected for the other non-wood raw materials. The study confirms the feasibility of organocell yield pulping process to Leucaena species. Organocell process provides an efficient delignification (kappa number 12.4 and pulp yield 42.2%) for L. leucocephala and suitably physical characteristics of paper sheet (tensile index 20.3kNm/kg for L. diversifolia). [Copyright &y& Elsevier]

Abstract: In this work, we characterized various unconventional pulping raw materials in terms of their contents in hollocelulose, α-cellulose, lignin, ethanol–benzene extractables, ash, and hot water and 1% soda solubles. Also, we characterized pulp obtained from each material by using an ethyleneglycol concentration of 65% at 180°C for 75min, followed by beating at 1500 revolutions in a PFI refiner—all of which are compatible with existing facilities for Kraft and soda pulping processes. We characterized vine shoots, cotton stalks, Leucaena leucocephala and Chamaecytisus proliferus as pulping raw materials and found Ch. proliferus and cotton stalks to be the best for the intended purpose on the grounds of their increased contents in holocellulose (79.73 and 72.86%) and α-cellulose (45.37 and 58.48%), and their decreased contents in ethanol–benzene extractables (2.64 and 1.42%), hot water solubles (2.79 and 3.33%) and 1% soda solubles (16.67 and 20.34%). These properties resulted in increased pulp yields and hence in efficient use of these two types of raw material. The paper sheets obtained of different pulps were characterized and those from Ch. proliferus found to be the best overall as they exhibited an increased breaking length (4644m), stretch (2.87%), burst index (2.46kN/g) tear index (0.33mNm2/g) and brightness (49.92% ISO); in addition Ch. proliferus pulp was obtained with a high yield (62.88%). On the other hand, vine shoots provided the poorest results among the studied raw materials. [Copyright &y& Elsevier]

Abstract: In order to identify faster-growing non-woody species usable for biomass and paper production, four Tagasastes (Chamaecytisus proliferus) from different origins are tested. All the Tagasaste species (T. Huelva, T. Australia, T. New Zealand and T. La Palma island) show a good soil and climatic adaptation to Southwest Spain. The studied Tagasaste provenances shows biomass productivity ranges from 1.0tha−1 yr−1 to 3.4tha−1 yr−1 (o.d.b.) and 25.3tha−1 yr−1 to 49.4tha−1 yr−1 under Mediterranean conditions for first and second year sprouts, respectively. The quantity of solubles and extractives shows similar values when compared with wood materials. A relatively lower lignin content in Tagasaste (from 13.7% to 17.1%) species has been found with respect to other vegetal species. The α-celullose contents (43.6–45.3%) were in the range of the normal values expected for the other non-wood raw materials. The study confirms the feasibility of the organocell yield pulping process to Tagasaste provenances. Organocell processes provide an efficient delignification (kappa index from 7.2 to 10.9 and pulp yield from 43.6% to 54.1%). The best results are obtained for the physical properties of paper sheets for Tagasaste from Australia in the second year, with values of tensile index of 16.0kNm/kg, burst index of 1.12MPam2/kg and tear index of 0.55Nm2/kg. [Copyright &y& Elsevier]

• Multidisciplinary evaluation of three novel perennial crops as feedstock for the pulp and paper industry. • Meadow hay blends generated higher tensile indices compared to the pure birch control. • Fibre lengths of 0.5 (meadow hay), 1.3 (Virginia mallow), and 0.9 mm (cup plant) were measured. • The fibre widths of cup plant and Virginia mallow are broader compared to hardwoods. • These promising raw materials will be valueable in cardboard production for sustainable packaging. While the demand for paper and packaging material is increasing, industry and consumers are searching for more sustainable raw materials. This study evaluates three non-wood perennials to find alternative raw materials for the paper and pulp industry. Meadow hay, cup plant (Silphium perfoliatum L.) and Virginia mallow (Sida hermaphrodita (L.) Rusby) are attracting attention as potential raw materials for the bioeconomy due to biodiversity benefits, low fertilizer requirements as well as high yields. For the first time a detailed view on their fibre morphology and use as paper feedstock is given. After three different mechanical grinding methods, the plant material was screened, pulped in NaOH and beaten in a PFI mill. Birch fibre has been chosen as short-fibre control and blend base. Hand-sheets with different pulp blends of birch and one of the three raw materials were made, and paper properties were measured. For meadow hay, Virginia mallow and cup plant fibre lengths of 0.5, 1.3, and 0.9 mm were measured. Therefore, all perennial plant materials have comparable fibre lengths to hardwoods. Meadow hay blends with birch pulp percentages of 50 % and 75 % generated higher paper strength compared to the pure birch paper at a beating intensity of 5000 revolutions (PFI). The paper strength of cup plant and Virginia mallow blends is comparable to the strength of the birch control. Due to these promising results, all analyzed raw materials could find their application, especially in the growing area of sustainable packaging materials. [ABSTRACT FROM AUTHOR]