Lignocellulosic materials as reinforcement and replacement for binders in masonry mortar

Background: Cross-linking structure of polyurethanes determines no degradability of these materials. However, introducing the hydrolysable substrates (of natural or synthetic origin) into the cross-linked polyurethanes structure makes them biodegradable. Moreover compounds (such as polycaprolactone triol, glycerin, lysine triisocyanate, etc.) that are used for polyurethane cross-linking are degraded in non-toxic products. All these kinds of compounds can be introduced into soft or hard segments via urethane bonds. Objective: The review focuses on kind of multifunctional polyols and isocyanates, and low molecular crosslinkers used for cross-linked polyurethanes obtaining. These compounds are natural substrates (in the native state or after modification) or are synthetic compounds with degradable linkages. They belong to polyesters, plant oils, proteins, saccharides, and others (e.g. lignocellulosic materials), and they are synthesized chemically or via biosynthesis by algae, plants, microorganisms, and by animals. Conclusion: Incorporation of degradable groups (such as ester moieties) into the polymer structure, and using of substrates with the structure known and metabolized by microorganisms for soft or hard segments building, facilitate degradation of cross-linked polyurethanes.

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State-of-the-Art Char Production with a Focus on Bark Feedstocks: Processes, Design, and Applications

Processes ◽

10.3390/pr9010087 ◽

2021 ◽

Vol 9 (1) ◽

pp. 87

Author(s):

Ali Umut Şen ◽

Helena Pereira

Keyword(s):

State Of The Art ◽

Lignocellulosic Materials ◽

Heating Rates ◽

Production Methods ◽

Slow Pyrolysis ◽

Production Studies ◽

Lignocellulosic Feedstocks ◽

Thermochemical Method ◽

Superior Surface ◽

First Time

In recent years, there has been a surge of interest in char production from lignocellulosic biomass due to the fact of char’s interesting technological properties. Global char production in 2019 reached 53.6 million tons. Barks are among the most important and understudied lignocellulosic feedstocks that have a large potential for exploitation, given bark global production which is estimated to be as high as 400 million cubic meters per year. Chars can be produced from barks; however, in order to obtain the desired char yields and for simulation of the pyrolysis process, it is important to understand the differences between barks and woods and other lignocellulosic materials in addition to selecting a proper thermochemical method for bark-based char production. In this state-of-the-art review, after analyzing the main char production methods, barks were characterized for their chemical composition and compared with other important lignocellulosic materials. Following these steps, previous bark-based char production studies were analyzed, and different barks and process types were evaluated for the first time to guide future char production process designs based on bark feedstock. The dry and wet pyrolysis and gasification results of barks revealed that application of different particle sizes, heating rates, and solid residence times resulted in highly variable char yields between the temperature range of 220 °C and 600 °C. Bark-based char production should be primarily performed via a slow pyrolysis route, considering the superior surface properties of slow pyrolysis chars.

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Use of non-thermal plasma in lignocellulosic materials: A smart alternative

Trends in Food Science & Technology ◽

10.1016/j.tifs.2021.01.047 ◽

2021 ◽

Vol 109 ◽

pp. 365-373

Author(s):

Gabriela N. Pereira ◽

Karina Cesca ◽

Anelise Leal Vieira Cubas ◽

Débora de Oliveira

Keyword(s):

Thermal Plasma ◽

Lignocellulosic Materials ◽

Non Thermal Plasma

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A Comprehensive Review on Advanced Sustainable Woven Natural Fibre Polymer Composites

Polymers ◽

10.3390/polym13030471 ◽

2021 ◽

Vol 13 (3) ◽

pp. 471

Author(s):

H. A. Aisyah ◽

M. T. Paridah ◽

S. M. Sapuan ◽

R. A. Ilyas ◽

A. Khalina ◽

...

Keyword(s):

Polymer Composites ◽

Polymeric Materials ◽

Major Effect ◽

Natural Fibre ◽

Natural Fibres ◽

Lignocellulosic Materials ◽

Structural Composites ◽

Detailed Review ◽

Green Materials ◽

Manufacturing Parameters

Over the last decade, the progressive application of natural fibres in polymer composites has had a major effect in alleviating environmental impacts. Recently, there is a growing interest in the development of green materials in a woven form by utilising natural fibres from lignocellulosic materials for many applications such as structural, non-structural composites, household utilities, automobile parts, aerospace components, flooring, and ballistic materials. Woven materials are one of the most promising materials for substituting or hybridising with synthetic polymeric materials in the production of natural fibre polymer composites (NFPCs). These woven materials are flexible, able to be tailored to the specific needs and have better mechanical properties due to their weaving structures. Seeing that the potential advantages of woven materials in the fabrication of NFPC, this paper presents a detailed review of studies related to woven materials. A variety of factors that influence the properties of the resultant woven NFRC such as yarn characteristics, fabric properties as well as manufacturing parameters were discussed. Past and current research efforts on the development of woven NFPCs from various polymer matrices including polypropylene, polylactic acid, epoxy and polyester and the properties of the resultant composites were also compiled. Last but not least, the applications, challenges, and prospects in the field also were highlighted.

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Effect of Chloride Ion Content and Replacement Ratio of Manufactured Sand on Performance of Sea Sand Masonry Mortar

Iranian Journal of Science and Technology Transactions of Civil Engineering ◽

10.1007/s40996-020-00539-x ◽

2021 ◽

Author(s):

Siyu Yang ◽

Zhenping Sun ◽

Zhengwu Jiang ◽

Zhenghong Yang ◽

Sifeng Liu

Keyword(s):

Chloride Ion ◽

Ion Content ◽

Replacement Ratio ◽

Manufactured Sand ◽

Sea Sand ◽

Masonry Mortar

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The impact of acid hydrolysis conditions on carbohydrate determination in lignocellulosic materials: a case study with Eucalyptus globulus bark

Holzforschung ◽

10.1515/hf-2020-0250 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Ricardo Jorge Oliveira ◽

Bruna Santos ◽

Maria J. Mota ◽

Susana R. Pereira ◽

Pedro C. Branco ◽

...

Keyword(s):

Acid Hydrolysis ◽

Eucalyptus Globulus ◽

Industrial Processes ◽

Lignocellulosic Materials ◽

Optimal Conditions ◽

Hydrolysis Conditions ◽

The Impact ◽

Eucalyptus Bark

Abstract Lignocellulosic biomass represents a suitable feedstock for production of biofuels and bioproducts. Its chemical composition depends on many aspects (e.g. plant source, pre-processing) and it has impact on productivity of industrial bioprocesses. Numerous methodologies can be applied for biomass characterisation, with acid hydrolysis being a particularly relevant step. This study intended to assess the most suitable procedures for acid hydrolysis, taking Eucalyptus globulus bark as a case study. For that purpose, variation of temperature (90–120 °C) was evaluated over time (0–5 h), through monosaccharides and oligosaccharides contents and degradation. For glucose, the optimal conditions were 100 °C for 2.5 h, reaching a content of 48.6 wt.%. For xylose, the highest content (15.2 wt.%) was achieved at 90 °C for 2 h, or 120 °C for 0.5 h. Maximum concentrations of mannose and galactose (1.0 and 1.7 wt.%, respectively) were achieved at 90 and 100 °C (2–3.5 h) or at 120 °C (0.5–1 h). These results revealed that different hydrolysis conditions should be applied for different sugars. Using this approach, total sugar quantification in eucalyptus bark was increased by 4.3%, which would represent a 5% increase in the ethanol volume produced, considering a hypothetical bioethanol production yield. This reflects the importance of feedstock characterization on determination of economic viability of industrial processes.

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Advances in Wood Composites III

Polymers ◽

10.3390/polym13010163 ◽

2021 ◽

Vol 13 (1) ◽

pp. 163

Author(s):

Antonios N. Papadopoulos

Keyword(s):

Lignocellulosic Materials ◽

Wood Composites

Wood composites are man-made materials that can be easily manufactured from a variety of raw lignocellulosic materials and the appropriate binder [...]

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