scholarly journals Sludge Fiber Waste and Kraft Lignin Powder as Fillers in Polylactic Acid Biocomposites: Physical, Mechanical, and Thermal Properties

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 672
Author(s):  
Thiago Souza da Rosa ◽  
Rosilani Trianoski ◽  
Franck Michaud ◽  
Fábio Yamashita ◽  
Setsuo Iwakiri

In this investigation, sludge fibre waste (SFW) and Kraft lignin powder (KLP) are introduced into polylactic acid (PLA) matrix biocomposites. These alternative materials allow for both the reuse of fibre waste from paper mill sludge and a reduction in the amount of high-cost biopolymer used in the same volume. Proportions from 10 to 40 wt.% of SFW with the addition of 2.5% and 5% of KLP are incorporated in PLA by extrusion and injection moulding. The thermogravimetric properties, water absorption, tensile and flexural properties, and morphology of the fabricated biocomposites were investigated. According to the results, KLP contributes to thermically stabilising the loss resulting from the incorporation of SFW. Flexural and tensile tests reveal a more pronounced decrease in strength with an SFW ratio above 10%. The modulus of elasticity increases significantly with an SFW ratio above 20%. The strength properties are stabilised with the addition of 5% KLP. The addition of KLP presents a tendency to reduce water absorption obtained by the incorporation of SFW into biocomposites. Scanning electron micrographs evidence that KLP improves the interfacial adhesion by reducing the voids between fibres and PLA.

2021 ◽  
Vol 72 (3) ◽  
pp. 299-307
Author(s):  
Naghmeh Amani ◽  
Ramin Vaysi ◽  
Abdollah Najafi ◽  
Seyed Eshagh Ebadi

This study aimed to scrutinize chemical treatment of Mazandaran Wood and Paper mill activated sludge with 3 % acetic acid for the manufacture of environmentally eco-friendly bio composite. In this study, the paper pulp required was obtained from the waste newsprint paper. The activated sludge was treated in a beaker for 3 min in 3 % acetic acid and then in a water bath at 75 and 100 °C for 45 and 90 min. After that, the treated activated sludge was mixed and refi ned with waste newsprint paper pulp at ratios of 0, 5, 10, 15 and 20 %. The test specimens were prepared according to TAPPI standard and the physical properties (water absorption and porosity) and mechanical (tensile strength, tear strength, ring crush test, burst strength and folding strength) were measured. The results showed that the activated sludge treatment caused the increase in tear strength, ring crush test, burst strength and porosity as well as the decrease in water absorption, tensile strength and folding strength. FT-IR spectrum of the treated samples showed that the treatment with acetic acid strengthened and activated the functional groups on the surface of activated sludge fi bers. The activated sludge added at a level of 5 % at 100 °C for 90 min as well as at a level of 20 % at 75 °C for 45 min was more suitable than other treatments.


BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 5538-5555
Author(s):  
Noor Afizah Rosli ◽  
Wan Hafizi Wan Ishak ◽  
Siti Salwani Darwis ◽  
Ishak Ahmad ◽  
Mohammad Fauzul Azim Mohd Khairudin

Enhancing the mechanical, thermal, and degradation properties of a poly(lactic acid) (PLA) blend without deteriorating its other useful features was the goal of this work. The isolation of cellulose nanocrystals (CNCs) from Agave angustifolia fibers was carried out, and the properties of the bio-nanocomposites comprising these CNCs were evaluated, which included PLA, natural rubber (NR), and liquid NR (LNR). Transmission electron microscopy and zeta potential analysis confirmed the successful isolation of CNCs from agave fibers after several chemical treatment steps. The effects of different CNC loadings on the properties of the bio-nanocomposites were investigated using tensile tests, thermal analysis, morphological analysis, and water absorption tests. Bio-nanocomposites containing 5 wt% and 7.5 wt% CNC had the optimal tensile modulus and strength, respectively. Different levels of CNC did not noticeably affect the thermal stability of the bio-nanocomposites, although the thermogram curves increased slightly as CNC content increased. The addition of CNC at different loadings affects the crystallization rate of PLA blend. The water absorption capacity increased as CNC level increased, and 5 wt% CNC gave rise to the highest water absorption. The four-component bio-nanocomposites created in this study provided an alternative for producing new green materials with tunable physical, mechanical, and thermal properties.


BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 4237-4251
Author(s):  
Naghmeh Amani Bishehgah ◽  
Ramin Vaysi ◽  
Majid Kiaei ◽  
Abdollah Najafi ◽  
Seyed Eshagh Ebadi

The present research aims to shed light on the effect of activated sludge (from a paper mill) and nanochitosan on the physical and strength properties of recycled pulp. Firstly, activated sludge was treated with 3% acetic acid for 30 min and then placed in a beaker for 90 min at 100 °C. Then, the ingredients were mixed and refined with recycled newsprint pulp in different proportions (0, 5, 10, and 15%). Finally, 2% nanochitosan was optionally added. Test specimens were prepared according to TAPPI standards with a basis weight of 120 g/m2, and their physical (water absorption) and strength (tear strength, tensile strength, burst strength, and ring crush test) properties were measured and compared. The results showed that with the increase of untreated activated sludge in recycled paper pulp, the indicators of tear resistance, ring crush test, and burst strength decreased and water absorption increased. Strength properties increased and water adsorption decreased when adding activated sludge treated with 3% acetic acid. Through the addition of nanochitosan to activated sludge treated with acetic acid, a significant increase in strength properties and a decrease in water absorption were observed.


2021 ◽  
pp. 096739112110041
Author(s):  
Shakti Chauhan ◽  
N Raghu ◽  
Anand Raj

Polylactic acid (PLA) is blended with native starch or thermo plasticized starch (TPS) for preparing biodegradable composites. However, poor compatibility of PLA with starch results in the composites with inferior mechanical properties. This study examines the effect of Maleic Anhydride-Grafted-PLA (GMAPLA) coupling agent and its concentration on the extent of improvements in mechanical and thermal properties of PLA –TPS blends. Maleic anhydride was grafted on PLA in Haake torque rheometer, characterized and used as the coupling agent. PLA/TPS (wt/wt) blends (70/30 and 50/50) were prepared by twin screw extrusion. GMAPLA at three different levels 5%, 10% and 15% (wt%) with respect to PLA content was taken to study its effect on mechanical properties of blends. Presence of GMAPLA significantly improved the mechanical properties (tensile, flexural and impact strength) of TPS/PLA blends. Among the three concentrations, 10% GMAPLA in the blend was found to give the maximum improvement in strength properties. Dynamic mechanical analysis and thermo-gravimetric analysis indicated no significant effect of GMAPLA content on transition temperatures and thermal degradation behavior of the blends.


Author(s):  
Teuku Rihayat ◽  
Nurhanifa ◽  
Tezara Cionita

The aim of this work is to improve the mechanical, thermal and water absorption properties of PLCHZ composites. The formation of the composites are mixing polylactic acid with zinc oxide nanoparticles (ZnO) and chitosan as filler. It produced through the precipitation method using a water bath under a temperature of 60 oC. Five prepared samples are pure PLA, PLCH, PLCHZa, PLCHZb and PLCHZc.  The incorporating effect of fillers on the properties of samples is investigated in terms of mechanical, thermal and water absorbtion test. The result showed that mechanical and thermal properties increased with the addition of ZnO nanoparticles compared to pure PLA and PLCH. Nevertheless, those properties increased up to 2 wt% of ZnO nanoparticles loading but decreased when it content is increased up to 3 wt% and 4 wt%. PLCHZa with the smallest content of 2 wt% ZnO nanoparticles showed the highest value of 15 MPa in tensile strength and 330.6 oC in thermal resistant. In water absorbtion test, PLCHZc with 4 wt% ZnO has better absorb ability as well as the lowest percentage absorption rate of 0.02% to 0.03%. It can be conclude that ZnO nanoparticles play an important role in the main properties of polymer composites.


TAPPI Journal ◽  
2015 ◽  
Vol 14 (2) ◽  
pp. 73-81 ◽  
Author(s):  
GISELY SAMISTRARO ◽  
PETER W. HART ◽  
JORGE LUIZ COLODETTE ◽  
RICARDO PAIM

Eucalyptus dunii has been commercially used in southern Brazil because of its relatively good frost tolerance and adequate productivity in the winter months. More recently, interest has grown in cultivating Eucalyptus benthamii Maiden & Cambage, which presents even superior frost tolerance compared to E. dunii and is highly productive as well. The quality of E. benthamii for pulp production is not yet proven. Thus, the chemical, anatomical, and technological aspects of pulp made from E. benthamii were compared with those of E. dunii for unbleached paper production. Samples of E. benthamii chips were obtained and analyzed for their basic density, chemical composition, higher heating value, trace elemental analysis, and chip size distribution. The chips were kraft cooked using conditions that produced a 74 ± 6 kappa number. The pulps were characterized for kappa number, yield, viscosity, and morphologic characteristics (e.g., length, wall thickness, and coarseness). Black liquor was analyzed for total solids, organics, inorganics, sodium sulfide, sodium hydroxide, and sodium carbonate. Brownstocks were beaten at five different energy levels in a Valley beater, and the physical strength properties of 120 g/m² handsheets were measured to develop a beater curve. The results of this study showed differences in delignification between the two woods and lower pulp yield for E. benthamii , which are related to their chemical compositions and basic densities. The E. benthamii studied in this work exhibited higher amounts of lignin and extractives, lower carbohydrate content, and lower basic density. However, cooking a blend of the two woods afforded good results in pulping and in physical pulp properties.


Buildings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 300
Author(s):  
Md. Safiuddin ◽  
George Abdel-Sayed ◽  
Nataliya Hearn

This paper presents the water absorption and strength properties of short carbon fiber reinforced mortar (CFRM) composite. Four CFRM composites with 1%, 2%, 3%, and 4% short pitch-based carbon fibers were produced in this study. Normal Portland cement mortar (NCPM) was also prepared for use as the control mortar. The freshly mixed mortar composites were tested for workability, wet density, and entrapped air content. In addition, the hardened mortar composites were examined for compressive strength, splitting tensile strength, flexural strength, and water absorption at the ages of 7 and 28 days. The effects of different carbon fiber contents on the tested properties were observed. Test results showed that the incorporation of carbon fibers decreased the workability and wet density, but increased the entrapped air content in mortar composite. Most interestingly, the compressive strength of CFRM composite increased up to 3% carbon fiber content and then it declined significantly for 4% fiber content, depending on the workability and compaction of the mortar. In contrast, the splitting tensile strength and flexural strength of the CFRM composite increased for all fiber contents due to the greater cracking resistance and improved bond strength of the carbon fibers in the mortar. The presence of short pitch-based carbon fibers significantly strengthened the mortar by bridging the microcracks, resisting the propagation of these minute cracks, and impeding the growth of macrocracks. Furthermore, the water absorption of CFRM composite decreased up to 3% carbon fiber content and then it increased substantially for 4% fiber content, depending on the entrapped air content of the mortar. The overall test results suggest that the mortar with 3% carbon fibers is the optimum CFRM composite based on the tested properties.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Izhar Alam ◽  
Swati Sood ◽  
Chhaya Sharma

Abstract Mixed hardwood unbleached (UB) and final bleached (FB) pulp along with the pulp of intermediate bleaching stages from an integrated paper mill have been undertaken for this study. Headspace GC-MS analysis of these pulps was made to identify the odorous compounds which are volatile organic compounds (VOCs), generated during ageing for 60 days. The result showed that a number of pre-generated VOCs such as aliphatic hydrocarbons and aldehydes are observed in the pulp sample which might be came from the process and it has been observed that upon ageing at ambient conditions, some acid functionalized VOC were generated in the pulp. The generation of these VOCs were established by ATR-FTIR analysis and the results showed that intensity of peak absorbance near 3340  cm − 1 {\text{cm}^{-1}} and 1641  cm − 1 {\text{cm}^{-1}} which represents the –OH stretching of acidic functional group and C=O stretch of aldehyde and acidic functional groups increased after ageing. Generation of acid functionalized volatile compounds were observed more in bleached pulp than in unbleached pulp. Degree of polymerization (DP) is pretty much related to the strength of paper. DP of both unbleached and bleached pulp gets reduced upon ageing while more reduction were observed in bleached pulp. Bleached pulps are more prone to degrade as compared to the unbleached pulp in terms of strength properties such as tensile index, breaking length, burst and double fold were observed. 12.3 % and 21.8 % reduction in tensile index was observed for UB and final bleached FB pulp respectively. Burst index of UB and FB pulp were found reduced to 23.8 % and 41.9 % respectively due to ageing. Reduction in the mechanical and optical properties was also observed in intermediate bleaching stages. There is much evidence for the contribution of VOCs to the degradation of paper. The results are strongly suggested that acid functionalized volatile compounds can have strong effects on degradation of cellulosic paper.


2021 ◽  
Vol 320 ◽  
pp. 181-185
Author(s):  
Elvija Namsone ◽  
Genadijs Sahmenko ◽  
Irina Shvetsova ◽  
Aleksandrs Korjakins

Because of low calcination temperature, magnesia binders are attributed as low-CO2 emission materials that can benefit the environment by reducing the energy consumption of building sector. Portland cement in different areas of construction can be replaced by magnesia binder which do not require autoclave treatment for hardening, it has low thermal conductivity and high strength properties. Magnesium-based materials are characterized by decorativeness and ecological compatibility.The experimental part of this research is based on the preparation of magnesia binders by adding raw materials and calcinated products and caustic magnesia. The aim of this study was to obtain low-CO2 emission and eco-friendly material using local dolomite waste materials, comparing physical, mechanical, thermal properties of magnesium binders.


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