scholarly journals Effect of sodium alginate on properties of wheat straw/polylactic acid composites

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 6003-6014
Author(s):  
Xuanhao Zhang

To investigate the effect of sodium alginate (SA) on the properties of wheat straw/polylactic acid (PLA) composites, four kinds of composites with different SA contents (0 wt%, 5 wt%, 10 wt%, and 15 wt%)were prepared via injection molding. The mechanical properties, moisture absorption, thermal stability, and infrared spectrum of the four kinds of composites were tested and analyzed, and the microstructure of the tensile section of the composites was observed via scanning electron microscopy. The degradability of the composites was also analyzed. The results showed that the wheat straw/PLA composites with 5% SA had better mechanical properties. Their tensile strength was 15.8%, 5.4%, and 19% higher than those of 0%, 10%, and 15% SA, respectively. The impact strength of the 5% SA composites changed to an acceptable degree relative to the non-SA composites, which had an impact strength of 28% lower than that of 0% SA but 51.9% higher than that of the 15% SA composite. The 5% SA composites had less hygroscopicity and better thermal stability, and adding SA enhanced the degradability of the composites. As the SA content increased, degradability increased greatly.

2013 ◽  
Vol 781-784 ◽  
pp. 390-394
Author(s):  
Xiao Li Song ◽  
Ying Chen ◽  
Yu Zhi Xu ◽  
Chun Peng Wang

Polyacrylate microsphere with different core/shell ratio (mass ratio) were prepared by semi-continuous seed emulsion copolymerization using butyl acrylate (BA) and methyl methacrylate (MMA) as main monomers,which were used to toughen polylactic acid (PLA) after drying. The effect of core/shell ratio of polyacrylate toughening agent (ACR) on mechanical properties of PLA was studied. The results showed that when adding 8wt%ACR, the impact strength and elongation at break of PLA were both first increased and then decreased as increasing of core/shell ratio, while the tensile strength loss of PLA was little changed. It is found that the impact strength was increased about 24% than that of neat PLA as well as the elongation at break was increased from 2% to 12% when the ratio was 7/3, which was the best ratio.


2011 ◽  
Vol 284-286 ◽  
pp. 1886-1889 ◽  
Author(s):  
Xiao Ming Sang ◽  
Lei Zhang ◽  
Run Zeng Wang ◽  
Xing Gang Chen ◽  
Man An ◽  
...  

The polystyrene/styrene-ethylene/butylene-styrene composites were prepared by melt blending process in this paper. The mechanical properties of PS/SEBS composites were analyzed. The results showed that the impact strength of PS/SEBS composites could be increased with the content increasing of SEBS, meanwhile the tensile strength was lower than pure polystyrene. When the content of SEBS increased to 13 wt.%, the impact strength of PS/SEBS composites was 2.4 times higher than that of pure PS. The fractured surfaces of the specimens were characterized by scanning electron microscopy(SEM). The results showed that the impact fractured surfaces produced a lot of sliding along with the addition of SEBS. The particles of SEBS could be well dispersed in polystyrene matrix. From rheological properties studies and the values of the torque, it was suggested that the maximum torque of PS/SEBS composites decreased drastically.


2020 ◽  
pp. 152808372092477 ◽  
Author(s):  
Adane Dagnaw Gudayu ◽  
Leif Steuernagel ◽  
Dieter Meiners ◽  
Rotich Gideon

Natural fibers are increasingly being used as composite reinforcement for both thermoplastic and thermoset resin, mainly for automotive application. Due to their hydrophilic nature, natural fibers have certain limitations during composite manufacture especially owing to their poor resin wettability, weak fiber–polymer interface, high moisture absorption, and being affected by high temperature in case of thermoplastic resin. This work investigates the impact of sisal fiber modification techniques on moisture absorption, thermal, and mechanical properties of the fiber. Four sisal fiber samples were prepared; untreated, alkaline treated, acetylated, and a combined alkaline-treated/acetylation samples. The samples were evaluated for their hygroscopic nature, thermal stability, and tensile properties. It is found that acetylation resulted in a reduction of moisture absorption of sisal fiber as the acetylated and alkaline-treated/acetylated samples recorded a decrease of 42% and 28%, respectively. Alkaline treatment increased the absorbency owing to the removal of hemicellulose and lignin. The thermogravimetric result revealed that alkaline treatment improved the thermal stability as the alkali-treated and alkali-treated/acetylated samples showed improvement in thermal properties. The acetylated sample resulted in a significant reduction in tensile strength. But, the results from tensile tests of the alkaline-treated samples showed an insignificant decrease in tensile strength and improvement in the modulus for all treated samples. Fourier-transform infrared and scanning electron microscopic analysis were included in the study to supplement the results with structural and microstructural changes. The effect of those treatments on the sisal–PET composite properties was studied and will be submitted in part 2 of the study.


2019 ◽  
Vol 11 (21) ◽  
pp. 6054
Author(s):  
Anna Keskisaari ◽  
Timo Kärki ◽  
Tommi Vuorinen

This study examines the mechanical properties of thermoplastic polymer composites manufactured by utilizing different side-stream materials as fillers. Two composites were manufactured from side-stream materials from the construction industry, two were manufactured from side-stream materials from the paper industry, and one was manufactured from side-stream materials from a coating factory. The matrix polymer used in the composites originated from recycling facility. The side-stream materials were used as fillers. One composite was manufactured as a reference by using wood-fiber as the filler. The tensile properties and impact strength were tested. The materials were also observed with a scanning electron microscope. Compared to the reference material, tensile strength and modulus decreased in all cases except for the sludge from the paper industry. The sludge also improved the impact strength remarkably, as the impact strength with the stone wool and stone dust from the construction industry remained the same, while the values were weakened for the others. Scanning electron microscope images showed that powder coating waste from the coating factory increased porosity and, thus, decreased the density of the material.


2018 ◽  
Vol 917 ◽  
pp. 42-46 ◽  
Author(s):  
Akshay Kakar ◽  
Elammaran Jayamani ◽  
Muhammad Khusairy bin Bakri ◽  
Soon Kok Heng

The goal of this study was to investigate the influence of cyclic hot and cold water absorption and desorption on the flexural and impact strengths of luffa – PLA biocomposites. PLA was reinforced with heat treated luffa fibers with the fiber loadings: 5 vol.%, 10 vol.%, 15 vol.% and 20 vol.%. Based on the test results the biocomposite with the highest flexural and impact strengths was selected for water absorption and desorption cycles. The biocomposites were subjected to 56 cycles of hot and cold water absorption and desorption. The biocomposites were tested for their strengths after every 14 cycles. The absorption and desorption decreased the flexural and impact strengths, affecting the impact strength more than the flexural strength.


Author(s):  
Zahid Iqbal Khan ◽  
Zurina Binti Mohamad ◽  
Abdul Razak Bin Rahmat ◽  
Unsia Habib ◽  
Nur Amira Sahirah Binti Abdullah

This work explores a novel blend of recycled polyethylene terephthalate/polyamide 11 (rPET/PA11). The blend of rPET/PA11 was introduced to enhance the mechanical properties of rPET at various ratios. The work’s main advantage was to utilize rPET in thermoplastic form for various applications. Three different ratios, i.e. 10, 20 and 30 wt.% of PA11 blend samples, were prepared using a twin-screw extruder and injection moulding machine. The mechanical properties were examined in terms of tensile, flexural and impact strength. The tensile strength of rPET was improved more than 50%, while the increase in tensile strain was observed 42.5% with the addition of 20 wt.% of PA11. The improved properties of the blend were also confirmed by the flexural strength of the blends. The flexural strength was increased from 27.9 MPa to 48 MPa with the addition of 30 wt.% PA11. The flexural strain of rPET was found to be 1.1%. However, with the addition of 10, 20 and 30 wt.% of PA11, the flexural strain was noticed as 1.7, 2.1, and 3.9% respectively. The impact strength of rPET/PA11 at 20 wt.% PA11 was upsurged from 110.53 to 147.12 J/m. Scanning electron microscopy analysis revealed a dispersed PA11 domain in a continuous rPET matrix morphology of the blends. This work practical implication would lead to utilization of rPET in automobile, packaging, and various industries.


2013 ◽  
Vol 844 ◽  
pp. 53-56
Author(s):  
Saravalee Saengthaveep ◽  
Sadhan C. Jana ◽  
Rathanawan Magaraphan

To produce a tough material for application demanding high impact resistance and low moisture absorption, melt blending of Nylon12 (Polyamide 12, PA12) and natural rubber (NR) was carried out in a brabender plasticorder at 210 °C with rotor speed of 70 rpm in the presence of polystyrene/maleated natural rubber (PS/MNR) blend as a compatibilizer. The effect of compatibilizer content (1, 3, 5, 7 and 10 phr) on phase morphology, thermal, and mechanical properties of [Nylon12/NR]/[PS/MNR] blends was investigated by using SEM, DSC, and Izod impact tester, respectively. The result revealed that PS/MNR blend improved the compatibility of Nylon12/NR blends efficiently due to the presence of amide linkage at the interfaces from the reaction between the reactive groups of MNR and the NH2 end groups of Nylon12 during mixing. A fine phase morphology (good dispersion and small dispersed phase size of NR domains in Nylon12 matrix) of [Nylon12/NR]/[PS/MNR] blends was observed at the optimum compatibilizer content of 7 phr, relating to the improvement of mechanical property. The impact energy of [Nylon12/NR]/[PS/MNR] blends was 503 J/m higher than that of neat Nylon12 (115 J/m) and Nylon12/NR binary blend (241 J/m) due to the toughening effect of rubber and proper morphology. The melting temperature of all blends did not change obviously from thermal analysis. However, the presence of rubber particle obstructed the crystallization of Nylon12 phase, leading to the decreasing of %crystallinity from 93% to around 70%.


Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 896 ◽  
Author(s):  
Qiqi Fan ◽  
Guangping Han ◽  
Wanli Cheng ◽  
Huafeng Tian ◽  
Dong Wang ◽  
...  

In this work, an easy way to prepare the polylactic acid (PLA)/wheat straw fiber (WSF) composite was proposed. The method involved uses either the dopamine-treated WSF or the two-step montmorillonite (MMT)-modified WSF as the filler material. In order to achieve the dispersibility and exfoliation of MMT, it was modified by 12-aminododecanoic acid using a two-step route. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were performed to characterize the modified MMT and the coated WSF. As for the properties of PLA/WSF composites, some thermal (using Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis) and mechanical properties (flexural, tensile, and impact) were analyzed. The results showed that the dopamine was successfully coated onto the WSF. Furthermore, Na-MMT was successfully transformed to organo-montmorillonite (OMMT) and formed an exfoliated structure. In addition, a better dispersion of MMT was obtained using the two-step treatment. The interlayer spacing of modified MMT was 4.06 nm, which was 123% higher than that of the unmodified MMT. Additionally, FT-IR analysis suggested that OMMT diffused into the PLA matrix. The thermogravimetric analysis (TGA) showed that a higher thermal stability of PLA/WSF composites was obtained for the modified MMT and dopamine. The results also showed that both the dopamine treated WSF and the two-step-treated MMT exhibited a positive influence on the mechanical properties of PLA/WSF composites, especially on the tensile strength, which increased by 367% compared to the unmodified precursors. This route offers researchers a potential scheme to improve the thermal and mechanical properties of PLA/WSF composites in a low-cost way.


2018 ◽  
Vol 777 ◽  
pp. 499-507 ◽  
Author(s):  
Ossi Martikka ◽  
Timo Kärki ◽  
Qing Ling Wu

3D printing has rapidly become popular in both industry and private use. Especially fused deposition modeling has increased its popularity due to its relatively low cost. The purpose of this study is to increase knowledge in the mechanical properties of parts made of wood-plastic composite materials by using 3D printing. The tensile properties and impact strength of two 3D-printed commercial wood-plastic composite materials are studied and compared to those made of pure polylactic acid. Relative to weight –mechanical properties and the effect of the amount of fill on the properties are also determined. The results indicate that parts made of wood-plastic composites have notably lower tensile strength and impact strength that those made of pure polylactic acid. The mechanical properties can be considered sufficient for low-stress applications, such as visualization of prototypes and models or decorative items.


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