scholarly journals Crazing Effect on the Bio-Based Conducting Polymer Film

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3425
Author(s):  
Pei-Yi Wong ◽  
Akiyoshi Takeno ◽  
Shinya Takahashi ◽  
Sook-Wai Phang ◽  
Azizah Baharum
Keyword(s):  
Weight Loss ◽  
Tensile Strength ◽  
Polymer Film ◽  
Polymer Chain ◽  
Tensile Strain ◽  
Young Modulus ◽  
Optical Microscope ◽  
Poly Lactic Acid ◽  
Pani Film ◽  
Polymer Waste

The biodegradability problem of polymer waste is one of the fatal pollutFions to the environment. Enzymes play an essential role in increasing the biodegradability of polymers. In a previous study, antistatic polymer film based on poly(lactic acid) (PLA) as a matrix and polyaniline (PAni) as a conductive filler, was prepared. To solve the problem of polymer wastes pollution, a crazing technique was applied to the prepared polymer film (PLA/PAni) to enhance the action of enzymes in the biodegradation of polymer. This research studied the biodegradation test based on crazed and non-crazed PLA/PAni films by enzymes. The presence of crazes in PLA/PAni film was evaluated using an optical microscope and scanning electron microscopy (SEM). The optical microscope displayed the crazed in the lamellae form, while the SEM image revealed microcracks in the fibrils form. Meanwhile, the tensile strength of the crazed PLA/PAni film was recorded as 19.25 MPa, which is almost comparable to the original PLA/PAni film with a tensile strength of 20.02 MPa. However, the Young modulus decreased progressively from 1113 MPa for PLA/PAni to 651 MPa for crazed PLA/PAni film, while the tensile strain increased 150% after crazing. The significant decrement in the Young modulus and increment in the tensile strain was due to the craze propagation. The entanglement was reduced and the chain mobility along the polymer chain increased, thus leading to lower resistance to deformation of the polymer chain and becoming more flexible. The presence of crazes in PLA/PAni film showed a substantial change in weight loss with increasing the time of degradation. The weight loss of crazed PLA/PAni film increased to 42%, higher than that of non-crazed PLA/PAni film with only 31%. The nucleation of crazes increases the fragmentation and depolymerization of PLA/PAni film that induced microbial attack and led to higher weight loss. In conclusion, the presence of crazes in PLA/PAni film significantly improved enzymes’ action, speeding up the polymer film’s biodegradability.

scholarly journals Thermo-Mechanical and Morphological Properties of Polymer Composites Reinforced by Natural Fibers Derived from Wet Blue Leather Wastes: A Comparative Study

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1837
Author(s):  
Alessandro Nanni ◽  
Mariafederica Parisi ◽  
Martino Colonna ◽  
Massimo Messori
Keyword(s):  
Tensile Strength ◽  
Polymer Matrix ◽  
Thermoplastic Polyurethane ◽  
Young Modulus ◽  
Morphological Properties ◽  
Poly Lactic Acid ◽  
Matrix Adhesion ◽  
The Poor ◽  
Leather Wastes ◽  
Fiber Matrix

The present work investigated the possibility to use wet blue (WB) leather wastes as natural reinforcing fibers within different polymer matrices. After their preparation and characterization, WB fibers were melt-mixed at 10 wt.% with poly(lactic acid) (PLA), polyamide 12 (PA12), thermoplastic elastomer (TPE), and thermoplastic polyurethane (TPU), and the obtained samples were subjected to rheological, thermal, thermo-mechanical, and viscoelastic analyses. In parallel, morphological properties such as fiber distribution and dispersion, fiber–matrix adhesion, and fiber exfoliation phenomena were analyzed through a scanning electron microscope (SEM) and energy-dispersive spectroscopy (EDS) to evaluate the relationship between the compounding process, mechanical responses, and morphological parameters. The PLA-based composite exhibited the best results since the Young modulus (+18%), tensile strength (+1.5%), impact (+10%), and creep (+5%) resistance were simultaneously enhanced by the addition of WB fibers, which were well dispersed and distributed in and significantly branched and interlocked with the polymer matrix. PA12- and TPU-based formulations showed a positive behavior (around +47% of the Young modulus and +40% of creep resistance) even if the not-optimal fiber–matrix adhesion and/or the poor de-fibration of WB slightly lowered the tensile strength and elongation at break. Finally, the TPE-based sample exhibited the worst performance because of the poor affinity between hydrophilic WB fibers and the hydrophobic polymer matrix.

scholarly journals On the use of nano fibrillated kenaf cellulose fiber as reinforcement in polylactic acid biocomposites

2019 ◽  
Vol 13 (2) ◽  
pp. 4970-4988 ◽  
Author(s):  
Q. Ahsan ◽  
T. S. S. Carron ◽  
Z. Mustafa
Keyword(s):  
Tensile Strength ◽  
Average Length ◽  
Synergistic Effects ◽  
Cellulose Fiber ◽  
Optical Microscope ◽  
Morphological Properties ◽  
Poly Lactic Acid ◽  
Maximum Increase ◽  
New Strategy ◽  
Mechanical Fibrillation

In this study, nano fibrillated kenaf cellulose (NFKC) derived from kenaf fiber after varying chemico-mechanical treatments were introduced into poly lactic acid (PLA) as reinforcements to improve the mechanical and morphological properties of the biocomposites. The new strategy was aiming to realize the synergistic effects of chemical treatment and mechanical fibrillation process parameters (blending speed and time) for yielding nano fibers and its reinforcement effects on the properties of biocomposites. The yield percentage of the NFKC was determined using centrifugal method and the NFKC fibers with PLA pellet were hot pressed to form NFKC-PLA composites. The distribution and dispersion morphologies of NFKC in NFKC-PLA composites were observed by using optical microscope (OM) and scanning electron microscope (SEM). The reinforcing effect on the mechanical properties of NFKC-PLA composite was investigated by tensile strength test. Average length and diameter of fibrillated fibers were decreased with the concurrent increase of blending speed and time. The maximum increase in tensile strength of 59.32% and elongation of 100% were observed for NFKC-PLA composite with NFKC yielded at a blending speed and time of 15000 rpm and 15 minutes as compared to pure PLA. The tensile properties indicated that the strength and modulus were improved with increased nanofiber contents.

scholarly journals Bioplastic Biodegradation Based on Ganyong Umbi States with Addition of Sorbitol and CMC (Carboxy Methil Cellulose) In Soil Media

2020 ◽  
Vol 3 ◽  
pp. 429-435
Author(s):  
Lukman Ma’arif ◽  
Ulia Fitrass ◽  
Endaruji Sedyadi
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Tensile Strength ◽  
Functional Groups ◽  
Young Modulus ◽  
Blending Method ◽  
Soil Media ◽  
Biodegradation Testing

Bioplastics made using the basic ingredients of canna tuber starch with sorbitol plasticizer and the addition of CMC variations have been carried out. This study aims to understand the effect of adding CMC to the mechanical properties and biodegradability of bioplastics in soil media. This research was carried out with 4 stages of work namely, extraction of starch from canna tubers, synthesis of bioplastic manufacturing using the blending method, testing mechanical properties in the form of thickness, tensile strength, elongation, and young modulus. Characteristics of functional groups have been tested using FTIR and bioplastic biodegradability testing has been carried out on soil media for 21 days by looking at weight loss from bioplastics. The variation of adding CMC used is 0; 0.25; 0.5; 0.75; 1; 1.25; 1.5 and 2 grams. The best mechanical properties are produced with thickness of 0.0795 mm, tensile strength of 27.53 MPa, elongation of 3.018% and young modulus of 885.66 MPa. The results of bioplastic biodegradation testing on soil media for 21 days showed that bioplastics made were biodegradable. Reduction of bioplastic mass in soil media by 86,032%.

scholarly journals Carbon Source Starvation of a Sulfate-Reducing Bacterium–Elevated MIC Deterioration of Tensile Strength and Strain of X80 Pipeline Steel

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhong Li ◽  
Jike Yang ◽  
Huihua Guo ◽  
Sith Kumseranee ◽  
Suchada Punpruk ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Tensile Strength ◽  
Carbon Source ◽  
Tensile Strain ◽  
Ultimate Tensile Stress ◽  
Sulfate Reducing ◽  
Source Level ◽  
Pit Depth ◽  
Sessile Cell

It is known that starved sulfate-reducing bacterial biofilms corrode carbon steel more aggressively because they use electrons from elemental iron oxidation as an alternative source of energy. This work used carbon source starvation to vary MIC (microbiologically influenced corrosion) severity for studying subsequent MIC impacts on the degradation of X80 carbon steel mechanical properties. X80 square coupons and dogbone coupons were immersed in ATCC 1249 culture medium (200 ml in 450-ml anaerobic bottles) inoculated with Desulfovibrio vulgaris for 3-day pre-growth and then for an additional 14 days in fresh media with adjusted carbon source levels for starvation testing. After the starvation test, the sessile cell counts (cells/cm2) on the dogbone coupons in the bottles with carbon source levels of 0, 10, 50, and 100% (vs that in the full-strength medium) were 8.1 × 106, 3.2 × 107, 8.3 × 107, and 1.3 × 108, respectively. The pit depths from the X80 dogbone coupons were 1.9 μm (0%), 4.9 μm (10%), 9.1 μm (50%), and 6.4 μm (100%). The corresponding weight losses (mg/cm2) from the square coupons were 1.9 (0%), 3.3 (10%), 4.4 (50%), and 3.7 (100%). The 50% carbon source level had the combination of carbon starvation without suffering too much sessile cell loss. Thus, both its pit depth and weight loss were the highest. The electrochemical tests corroborated the pit depth and weight loss trends. The tensile tests of the dogbone coupons after the starvation incubation indicated that sulfate-reducing bacteria (SRB) made X80 more brittle and weaker. Compared with the fresh (no-SRB-exposure) X80 dogbone coupon’s ultimate tensile strain of 13.6% and ultimate tensile stress of 860 MPa, the 50% carbon source level led to the lowest ultimate tensile strain of 10.3% (24% loss when compared with the fresh dogbone) and ultimate tensile stress of 672 MPa (22% loss). The 100% carbon source level had a smaller loss in ultimate tensile strain than the 50% carbon source level, followed by 10% and then 0%. Moreover, the 100% carbon source level had a smaller loss in ultimate tensile strength than the 50%, followed by 10% and 0% in a tie. This outcome shows that even in the 17-day short-term test, significant degradation of the mechanical properties occurred and more severe MIC pitting caused more severe degradation.

Effect of Polyethylene Glycol in Nanocellulose/PLA Composites

2019 ◽  
Vol 821 ◽  
pp. 89-95
Author(s):  
Wanasorn Somphol ◽  
Thipjak Na Lampang ◽  
Paweena Prapainainar ◽  
Pongdhorn Sae-Oui ◽  
Surapich Loykulnant ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Lactic Acid ◽  
Polyethylene Glycol ◽  
Aspect Ratio ◽  
Mechanical Performance ◽  
Tensile Modulus ◽  
Poly Lactic Acid ◽  
Solvent Casting ◽  
Casting Method ◽  
Mediated Oxidation

Poly (lactic acid) or PLA was reinforced by nanocellulose and polyethylene glycol (PEG), which were introduced into PLA matrix from 0 to 3 wt.% to enhance compatibility and strength of the PLA. The nanocellulose was prepared by TEMPO-mediated oxidation from microcrystalline cellulose (MCC) powder and characterized by TEM, AFM, and XRD to reveal rod-like shaped nanocellulose with nanosized dimensions, high aspect ratio and high crystallinity. Films of nanocellulose/PEG/PLA nanocomposites were prepared by solvent casting method to evaluate the mechanical performance. It was found that the addition of PEG in nanocellulose-containing PLA films resulted in an increase in tensile modulus with only 1 wt% of PEG, where higher PEG concentrations negatively impacted the tensile strength. Furthermore, the tensile strength and modulus of nanocellulose/PEG/PLA nanocomposites were higher than the PLA/PEG composites due to the existence of nanocellulose chains. Visual traces of crazing were detailed to describe the deformation mechanism.

scholarly journals Study on the Dissolution and Precipitation Behavior of Self-Designed (NbTi)C Nanoparticles Addition in 1045 Steel

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 184
Author(s):  
Hongwei Zhu ◽  
Haonan Li ◽  
Furen Xiao ◽  
Zhixiang Gao
Keyword(s):  
Tensile Strength ◽  
Electron Microscope ◽  
Optical Microscope ◽  
Cast Steels ◽  
Uniform Dispersion ◽  
The Matrix ◽  
Thermo Calc Software ◽  
Particle Strengthening ◽  
1045 Steel ◽  
Addition Amount

Self-designed (NbTi)C nanoparticles were obtained by mechanical alloying, predispersed in Fe powder, and then added to 1045 steel to obtain modified cast steels. The microstructure of cast steels was investigated by an optical microscope, scanning electron microscope, X-ray diffraction, and a transmission electron microscope. The results showed that (NbTi)C particles can be added to steels and occur in the following forms: original ellipsoidal morphology nanoparticles with uniform dispersion in the matrix, cuboidal nanoparticles in the grain, and microparticles in the grain boundary. Calculations by Thermo-Calc software and solubility formula show that cuboidal (NbTi)C nanoparticles were precipitated in the grain, while the (NbTi)C microparticles were formed by eutectic transformation. The results of the tensile strength of steels show that the strength of modified steels increased and then declined with the increase in the addition amount. When the addition amount was 0.16 wt.%, the modified steel obtained the maximum tensile strength of 759.0 MPa, which is an increase of 52% compared with to that with no addition. The hardness of the modified steel increased with the addition of (NbTi)C nanoparticles. The performance increase was mainly related to grain refinement and the particle strengthening of (NbTi)C nanoparticles, and the performance degradation was related to the increase in eutectic (NbTi)C.

scholarly journals Biocomposites of Epoxidized Natural Rubber/Poly(lactic acid) Modified with Natural Fillers (Part I)

2021 ◽  
Vol 22 (6) ◽  
pp. 3150
Author(s):  
Anna Masek ◽  
Stefan Cichosz ◽  
Małgorzata Piotrowska
Keyword(s):  
Tensile Strength ◽  
Lactic Acid ◽  
Natural Rubber ◽  
Epoxidized Natural Rubber ◽  
Poly Lactic Acid ◽  
Uv Aging ◽  
High Elasticity ◽  
Natural Fillers ◽  
Natural Additives

The study aimed to prepare sustainable and degradable elastic blends of epoxidized natural rubber (ENR) with poly(lactic acid) (PLA) that were reinforced with flax fiber (FF) and montmorillonite (MMT), simultaneously filling the gap in the literature regarding the PLA-containing polymer blends filled with natural additives. The performed study reveals that FF incorporation into ENR/PLA blend may cause a significant improvement in tensile strength from (10 ± 1) MPa for the reference material to (19 ± 2) MPa for the fibers-filled blend. Additionally, it was found that MMT employment in the role of the filler might contribute to ENR/PLA plasticization and considerably promote the blend elongation up to 600%. This proves the successful creation of the unique and eco-friendly PLA-containing polymer blend exhibiting high elasticity. Moreover, thanks to the performed accelerated thermo-oxidative and ultraviolet (UV) aging, it was established that MMT incorporation may delay the degradation of ENR/PLA blends under the abovementioned conditions. Additionally, mold tests revealed that plant-derived fiber addition might highly enhance the ENR/PLA blend’s biodeterioration potential enabling faster and more efficient growth of microorganisms. Therefore, materials presented in this research may become competitive and eco-friendly alternatives to commonly utilized petro-based polymeric products.

scholarly journals Performance Evaluation of Cellulose Nanofiber with Residual Hemicellulose as a Nanofiller in Polypropylene-Based Nanocomposite

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1064
Author(s):  
Mohd Nor Faiz Norrrahim ◽  
Hidayah Ariffin ◽  
Tengku Arisyah Tengku Yasim-Anuar ◽  
Mohd Ali Hassan ◽  
Nor Azowa Ibrahim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Weight Loss ◽  
Tensile Strength ◽  
Performance Evaluation ◽  
Flexural Strength ◽  
Decomposition Temperature ◽  
Cellulose Nanofiber ◽  
Hemicellulose Removal ◽  
Reinforcement Material

Residual hemicellulose could enhance cellulose nanofiber (CNF) processing as it impedes the agglomeration of the nanocellulose fibrils and contributes to complete nanofibrillation within a shorter period of time. Its effect on CNF performance as a reinforcement material is unclear, and hence this study seeks to evaluate the performance of CNF in the presence of amorphous hemicellulose as a reinforcement material in a polypropylene (PP) nanocomposite. Two types of CNF were prepared: SHS-CNF, which contained about 11% hemicellulose, and KOH-CNF, with complete hemicellulose removal. Mechanical properties of the PP/SHS-CNF and PP/KOH-CNF showed an almost similar increment in tensile strength (31% and 32%) and flexural strength (28% and 29%) when 3 wt.% of CNF was incorporated in PP, indicating that hemicellulose in SHS-CNF did not affect the mechanical properties of the PP nanocomposite. The crystallinity of both PP/SHS-CNF and PP/KOH-CNF nanocomposites showed an almost similar value at 55–56%. A slight decrement in thermal stability was seen, whereby the decomposition temperature at 10% weight loss (Td10%) of PP/SHS-CNF was 6 °C lower at 381 °C compared to 387 °C for PP/KOH-CNF, which can be explained by the degradation of thermally unstable hemicellulose. The results from this study showed that the presence of some portion of hemicellulose in CNF did not affect the CNF properties, suggesting that complete hemicellulose removal may not be necessary for the preparation of CNF to be used as a reinforcement material in nanocomposites. This will lead to less harsh pretreatment for CNF preparation and, hence, a more sustainable nanocomposite can be produced.

scholarly journals Bonding Wood Veneer with Biobased Poly(Lactic Acid) Thermoplastic Polyesters: Potential Applications for Consolidated Wood Veneer and Overlay Products

Fibers ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 50
Author(s):  
Warren J. Grigsby ◽  
Arpit Puri ◽  
Marc Gaugler ◽  
Jan Lüedtke ◽  
Andreas Krause
Keyword(s):  
Tensile Strength ◽  
Lactic Acid ◽  
Cold Water ◽  
Performance Criteria ◽  
Poly Lactic Acid ◽  
Wood Veneer ◽  
Pressing Temperature ◽  
Strength Performance ◽  
Potential Applications ◽  
Laminated Panels

This study reports on the use of poly(lactic acid) (PLA) as a renewable thermoplastic adhesive for laminated panels using birch, spruce, and pine veneers. Consolidated panels were prepared from veneer and PLA foils by hot-pressing from 140 to 180 °C to achieve minimum bondline temperatures. Evaluation of panel properties revealed that the PLA-bonded panels met minimum tensile strength and internal bond strength performance criteria. However, the adhesion interface which developed within individual bondlines varied with distinctions between hardwood and softwood species and PLA grades. Birch samples developed greater bondline strength with a higher pressing temperature using semi-crystalline PLA, whereas higher temperatures produced a poorer performance with the use of amorphous PLA. Panels formed with spruce or pine veneers had lower bondline performance and were also similarly distinguished by their pressing temperature and PLA grade. Furthermore, the potential for PLA-bonded laminated panels was demonstrated by cold water soak testing. Samples exhibiting relatively greater bondline adhesion had wet tensile strength values comparable to those tested in dry state. Our study outcomes suggest the potential for PLA bonding of veneers and panel overlays with the added benefits of being renewable and a no added formaldehyde system.

Properties of Random PSF/PES Copolymers as High-Performance Polymers

2011 ◽  
Vol 217-218 ◽  
pp. 1606-1610
Author(s):  
Dong Jiang ◽  
Xiao Ran Zhang ◽  
Yan Mei Ma ◽  
Cheng You Ma
Keyword(s):  
Weight Loss ◽  
Tensile Strength ◽  
Glass Transition ◽  
High Performance ◽  
Molar Ratio ◽  
Transition Temperatures ◽  
Elongation At Break ◽  
Glass Transition Temperatures ◽  
High Performance Polymers ◽  
Diphenyl Sulfone

A series of random polysulfone/polyethersulfone (PSF/PES) copolymers were synthesized by the polycondensation of 4, 4'-isopropylidendiphenol, 4, 4΄-dihyolroxy diphenyl sulfone and 4, 4'-dichlorodiphenyl sulfone in the presence of K2CO3. We obtained a series of copolymers by changing the molar ratio of 4, 4΄-dihyolroxy diphenyl sulfone and 4, 4'-isopropylidendiphenol (it was marked as the ratio of S:A). The copolymers have the similar solubility with polyethersulfone. They also have high glass transition temperatures (Tg: 199°C~229°C) and 5% weight loss temperatures (4, 4'-isopropylidendiphenol: 4, 4΄-dihyolroxy diphenyl sulfone=1:1, Td5=497°C). At the same time the elongation at break is much higher than that of PES, while the tensile strength is a little lower than that of PES.

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