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 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.

Hybrid Nanocomposites of Poly(Lactic Acid)/Thermoplastic Polyurethane with Nanosilica/Montmorillonite

2019 ◽  
Vol 947 ◽  
pp. 77-81
Author(s):  
Natsuda Palawat ◽  
Phasawat Chaiwutthinan ◽  
Sarintorn Limpanart ◽  
Amnouy Larpkasemsuk ◽  
Anyaporn Boonmahitthisud
Keyword(s):  
Thermal Stability ◽  
Tensile Strength ◽  
Impact Strength ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Thermoplastic Polyurethane ◽  
Hybrid Nanocomposites ◽  
Poly Lactic Acid ◽  
Elongation At Break ◽  
Thermal Stability Of

The aim of this study is to improve the physical properties of poly(lactic acid) (PLA) by incorporating thermoplastic polyurethane (TPU), organo-montmorillonite (OMMT) and/or nanosilica (nSiO2). PLA was first melt mixed with five loadings of TPU (10–50 wt%) on a twin-screw extruder, followed by injection molding. The addition of TPU was found to increase the impact strength, elongation at break and thermal stability of the blends, but decrease the tensile strength and Young’s modulus. Based on a better combination of the mechanical properties, the 70/30 (w/w) PLA/TPU blend was selected for preparing both single and hybrid nanocomposites with a fix total nanofiller content of 5 parts per hundred of resin (phr), and the OMMT/nSiO2 weight ratios were 5/0, 2/3, 3/2 and 0/5 (phr/phr). The Young’s modulus and thermal stability of the nanocomposites were all higher than those of the neat 70/30 PLA/TPU blend, but at the expense of reducing the tensile strength, elongation at break and impact strength. However, all the nanocomposites exhibited higher impact strength and Young’s modulus than the neat PLA. Among the four nanocomposites, a single-filler nanocomposite containing 5 phr nSiO2 exhibited the highest impact strength and thermal stability, indicating that there was no synergistic effect of the two nanofillers on the investigated physical properties. However, the hybrid nanocomposite containing 2/3 (phr/phr) OMMT/nSiO2 possessed a compromise in the tensile properties.

Effects of Mixing Parameters on Tensile Strength of TPU/NR Blends

2013 ◽  
Vol 291-294 ◽  
pp. 2654-2656
Author(s):  
Nor Azwin Ahad ◽  
Sahrim Hj Ahmad ◽  
Norazwani Muhammad Zain
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Natural Rubber ◽  
Polymer Blends ◽  
Mixing Time ◽  
Thermoplastic Polyurethane ◽  
Mixing Times ◽  
Melt Mixing ◽  
Mixing Parameters ◽  
The Poor

The blends of thermoplastic polyurethane (TPU) with natural rubber (NR) were prepared via melt mixing technique, at four different blending temperature at range 180°C - 210°C and mixing times of 8, 10, 12, 14 min. The effects of both mixing parameters on tensile strength of the blends were investigated. The blend of 85TPU15NR shows the maximum tensile strength at 180°C and 10 min mixing. The viscosity of the polymer blends will decrease as the temperature increased. The movements of molecules are more worthy because of the poor molecules interaction. The increasing of mixing time will increase the compatibility of the blends and also increase in mechanical properties. Mixing time and mixing temperature are important parameters in acquiring blends having optimum mechanical properties.

scholarly journals Enhancement of Static and Fatigue Strength of Short Sisal Fiber Biocomposites by Low Fraction Nanotubes

2021 ◽  
Author(s):  
A. Pantano ◽  
F. Bongiorno ◽  
G. Marannano ◽  
B. Zuccarello
Keyword(s):  
Carbon Nanotubes ◽  
Tensile Strength ◽  
Low Cost ◽  
Short Fiber ◽  
Fatigue Tests ◽  
Sisal Fiber ◽  
Molding Process ◽  
Matrix Adhesion ◽  
Fiber Matrix ◽  
Damage Processes

AbstractThanks to good mechanical performances, high availability, low cost and low weight, the agave sisalana fiber allows to obtain biocomposites characterised by high specific properties, potentially very attractive for the replacement of synthetic materials in various industrial fields. Unfortunately, due to the low strength versus transversal damage processes mainly related to the matrix brittleness and/or to the low fiber/matrix adhesion, the tensile performance of random short fiber biocomposites are quite low, and to date most of the fiber treatments proposed in literature to improve the fiber-matrix adhesion, have not led to very satisfactory results. In order to overcome such a drawback, this work in turn proposes the proper introduction of low fractions carbon nanotubes to activate advantageous improvements in matrix toughness as well as fiber-matrix bridging effects, that can both lead to appreciable increments of the tensile strength.Systematic experimental static and fatigue tests performed on high quality biocomposites obtained by an optimized compression molding process, have shown that the introduction of 1% of carbon nanotubes is sufficient to gives significant improvement in both stiffness and static tensile strength, respectively by approximately 28% and 30%. Furthermore, toughening the biocomposite with 1% of nanotubes results in an appreciable enhancement in lifetime of at least 3 orders of magnitude. Biocomposites with 2% of CNTs show instead more limited improvement of 13% in stiffness, 6% in strength and 150% in lifetime. Also, a thorough analysis of the damage processes by SEM micrographs, as well as of the main fatigue data, has allowed to determine the model that can be used to predict the fatigue performance of such biocomposites.

Influence of Blend Proportions on Properties of ENR-25/TPU Simple Blends

2013 ◽  
Vol 844 ◽  
pp. 93-96
Author(s):  
Skulrat Pichaiyut ◽  
Charoen Nakason ◽  
Ekwipoo Kalkornsurapranee ◽  
Norbert Vennemann ◽  
Claudia Kummerlöwe
Keyword(s):  
Tensile Strength ◽  
Natural Rubber ◽  
Thermoplastic Polyurethane ◽  
Polymer Melt ◽  
Continuous Phase ◽  
Morphological Properties ◽  
Elongation At Break ◽  
Soft Segments ◽  
Lower Elongation ◽  
Thermoplastic Natural Rubber

Thermoplastic natural rubber (TPNR) based on blending of thermoplastic polyurethane (TPU) and epoxidized natural rubber with 25 mol % epoxide (ENR-25) was prepared by simple blend technique. Influence of various blend proportions was investigated. It was found that an incorporation of rubber caused decreasing of mechanical properties in terms of tensile strength, elongation at break and hardness. This is attributed to incorporation of rubber phase may cause chain restriction of the soft segments in TPU and hence lower elongation at break and tensile strength. It was also found that the tension set value decreased with increasing proportion of natural rubber which indicates greater elasticity or tendency to recover to the original shape after prolonged deformation. Additionally, shear stress and shear viscosity of the blends increased with increasing rubber proportions due to higher viscosity of the ENR-25 component which leads to higher force to compress the polymer melt flowing through a capillary channel. Morphological properties of the simple blend with various blend proportions exhibited formation of co-continuous phase structure was observed where larger rubber formation are observed in the blend with higher content of ENR-25 phase.

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.

Jute Fiber Reinforced Thermoplastic Composites Fabricated by Direct Fiber Feeding Injection Molding (DFFIM) Process

2020 ◽  
Vol 856 ◽  
pp. 268-275
Author(s):  
Prattakon Sarasook ◽  
Putinun Uawongsuwan ◽  
Anin Memon ◽  
Hiroyuki Hamada
Keyword(s):  
Tensile Strength ◽  
Injection Molding ◽  
Tensile Modulus ◽  
Jute Fiber ◽  
Morphological Properties ◽  
Thermoplastic Composites ◽  
Poly Lactic Acid ◽  
Fiber Reinforced ◽  
Molding Process ◽  
Spun Yarns

In this research, jute fiber reinforced polypropylene and poly (lactic acid) composites were fabricated, respectively by Direct Fiber Feeding Injection molding (DFFIM) process. Jute spun yarns were directly fed into the barrel of molding process in order to eliminate the fiber breakage during extrusion compounding process. Mechanical properties of both composites were investigated by tensile testing and morphological properties were characterized by scanning electron microscopy (SEM). For jute reinforced polypropylene (PP) composites, tensile strength of composite decreased but modulus increased, compared with neat PP. The using maleic anhydride grafted polypropylene (MaPP) can improve interfacial bonding between jute fiber and PP matrix as observed by SEM, which resulted in the increasing of tensile strength. Therefore, in the case of jute/PLA composites, jute fibers surface treated with sodium hydroxide (NaOH) and silane coupling agent to improve interfacial adhesion. The tensile strength of untreated-jute/PLA composites are not different with PLA matrix but tensile modulus of untreated composites are higher than PLA matrix. In addition it is found that the tensile properties of NaOH-treated jute/PLA and NaOH+Silane-treated jute/PLA composites were improved, compared with untreated composites.

Preparation and Properties Research of PA6/PLA Blends Toughening Modified by TPU

2012 ◽  
Vol 200 ◽  
pp. 278-281 ◽  
Author(s):  
Yi Chen ◽  
Wei Jian Xu ◽  
Guang Sheng Zeng ◽  
Xiao Hong Zeng ◽  
Wen Yong Liu ◽  
...  
Keyword(s):  
Tensile Strength ◽  
High Performance ◽  
Fracture Behavior ◽  
Thermoplastic Polyurethane ◽  
Polyamide 6 ◽  
Poly Lactic Acid ◽  
Melt Blending ◽  
Thermal And Mechanical Properties ◽  
Elongation At Break ◽  
The Impact

Polyamide 6/Poly(lactic acid) (PA6/PLA) blends introduce the degradability of PLA to high performance PA6, but the bad toughness of both PA6 and PLA limits the application of blends. Aiming at this deficiency, thermoplastic polyurethane (TPU) was used as an additive for modifying the toughness of PA6/PLA blends. PA6/PLA/TPU blends at various compositions were prepared by melt blending, the effects of blend compositions on the morphology, thermal and mechanical properties of blends were investigated. The results showed that the addition of TPU improves the compatibilization between PA6 and PLA and makes the blends show more obvious plastic fracture behavior than PA6/PLA.When the content of PLA in PA6/PLA increases, the impact and tensile strength of blends decrease slightly with the intense decrease of the elongation at break, adding TPU into PA6/PLA blends strengthens the toughness of blends, but the tensile strength of blends decreases. Moreover, the crystallinity of PA6 /PLA blend is hampered by TPU.

Properties of HDPE/Biodegradable Polymer Blends Using Modified Rubber

2017 ◽  
Vol 873 ◽  
pp. 101-106 ◽  
Author(s):  
Chanon Wiphanurat ◽  
Pran Hanthanon ◽  
Thiti Kaisone ◽  
Rathanawan Magaraphan ◽  
Tarinee Nampitch
Keyword(s):  
Tensile Strength ◽  
Polymer Blends ◽  
Biodegradable Polymer ◽  
Tensile Tests ◽  
Morphological Properties ◽  
Poly Lactic Acid ◽  
High Tensile Strength ◽  
Elongation At Break ◽  
Compatibilization Effect ◽  
Scanning Electron

Biodegradable blends consisting of poly(lactic acid) (PLA), poly(butylene adipate-coterephthalate) (PBAT) and epoxidized natural rubber (ENR) were blended in two proportions at PLA/PBAT/ENR ratios of 70/10/20 and 70/20/10. Then, blends these biodegradable polymers (PLA/PBAT/ENR) with HDPE at various ratios of 20/80, 10/90 and 5/95 wt%, the mechanical and morphological properties were investigated. Tensile tests of PLA/PBAT/ENR blends revealed high tensile strength and modulus but low elongation compared with HDPE. The tensile strength, elongation at break and impact strength of HDPE/biodegradable polymer blends decreased with increasing biodegradable polymer contents. Morphological properties of HDPE/biodegradable polymer blends were investigated by scanning electron microscope, which showed smoother surface of HDPE/biodegradable (70/10/20) than those of (70/20/10) polymer blends according to ENR compatibilization effect.

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