scholarly journals Research on the Strengthening Advantages on Using Cellulose Nanofibers as Polyvinyl Alcohol Reinforcement

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 974 ◽  
Author(s):  
Quim Tarrés ◽  
Helena Oliver-Ortega ◽  
Manel Alcalà ◽  
F. Xavier Espinach ◽  
Pere Mutjé ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Polyvinyl Alcohol ◽  
High Performance ◽  
Cellulose Nanofibers ◽  
Cellulosic Fibers ◽  
Reinforcement Content ◽  
Superior Mechanical Properties ◽  
Coupling Factors ◽  
Internal Mixer

The present work aims to combine the unique properties of cellulose nanofibers (CNF) with polyvinyl alcohol (PVA) to obtain high-performance nanocomposites. CNF were obtained by means of TEMPO-mediated ((2,2,6,6-Tetramethylpiperidin-1-yl)oxyl) oxidation, incorporated into the PVA matrix by means of compounding in a single-screw co-rotating internal mixer and then processed by means of injection molding. It was found that CNF were able to improve the tensile strength of PVA in 85% when 4.50 wt % of CNF were added. In addition, the incorporation of a 2.25 wt % of CNF enhanced the tensile strength to the same level that when 40 wt % of microsized fibers (stone groundwood pulp, SGW) were incorporated, which indicated that CNF possessed significantly higher intrinsic mechanical properties than microsized fibers. SGW was selected as reference for microsized fibers due to their extended use in wood plastic composites. Finally, a micromechanical analysis was performed, obtaining coupling factors near to 0.2, indicating good interphase between CNF and PVA. Overall, it was found that the use of CNF is clearly advantageous to the use of common cellulosic fibers if superior mechanical properties are desired, but there are still some limitations that are related to processing that restrict the reinforcement content at low contents.

scholarly journals Effect of Length of Cellulose Nanofibers on Mechanical Reinforcement of Polyvinyl Alcohol

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 128
Author(s):  
Mengxia Wang ◽  
Xiaran Miao ◽  
Hui Li ◽  
Chunhai Chen
Keyword(s):  
Mechanical Properties ◽  
Polyvinyl Alcohol ◽  
High Performance ◽  
Mechanical Performance ◽  
Cellulose Nanofibers ◽  
Composite Films ◽  
Nanocomposite Films ◽  
Mechanical Reinforcement ◽  
Research Attention ◽  
Casting Technique

Cellulose nanofibers (CNF), representing the nano-structured cellulose, have attained an extensive research attention due to their sustainability, biodegradability, nanoscale dimensions, large surface area, unique optical and mechanical performance, etc. Different lengths of CNF can lead to different extents of entanglements or network-like structures through van der Waals forces. In this study, a series of polyvinyl alcohol (PVA) composite films, reinforced with CNF of different lengths, were fabricated via conventional solvent casting technique. CNF were extracted from jute fibers by tuning the dosage of sodium hypochlorite during the TEMPO-mediated oxidation. The mechanical properties and thermal behavior were observed to be significantly improved, while the optical transparency decreased slightly (Tr. > 75%). Interestingly, the PVA/CNF20 nanocomposite films exhibited higher tensile strength of 34.22 MPa at 2 wt% filler loading than the PVA/CNF10 (32.55 MPa) while displayed higher elastic modulus of 482.75 MPa than the PVA/CNF20 films (405.80 MPa). Overall, the findings reported in this study provide a novel, simple and inexpensive approach for preparing the high-performance polymer nanocomposites with tunable mechanical properties, reinforced with an abundant and renewable material.

EFFECT OF ZINC DITHIOCARBAMATES AND THIAZOLE-BASED ACCELERATORS ON THE VULCANIZATION OF NATURAL RUBBER

2012 ◽  
Vol 85 (1) ◽  
pp. 120-131 ◽  
Author(s):  
Md. Najib Alam ◽  
Swapan Kumar Mandal ◽  
Subhas Chandra Debnath
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Reaction Mechanism ◽  
Natural Rubber ◽  
High Performance ◽  
Binary Systems ◽  
Synergistic Activity ◽  
Tetramethylthiuram Disulfide

Abstract Several zinc dithiocarbamates (ZDCs) as accelerator derived from safe amine has been exclusively studied in the presence of thiazole-based accelerators to introduce safe dithiocarbamate in the vulcanization of natural rubber. Comparison has been made between conventional unsafe zinc dimethyldithiocarbamate (ZDMC) with safe novel ZDC combined with thizole-based accelerators in the light of mechanical properties. The study reveals that thiuram disulfide and 2-mercaptobenzothiazole (MBT) are always formed from the reaction either between ZDC and dibenzothiazyledisulfide (MBTS) or between ZDC and N-cyclohexyl-2-benzothiazole sulfenamide (CBS). It has been conclusively proved that MBT generated from MBTS or CBS reacts with ZDC and produces tetramethylthiuram disulfide. The observed synergistic activity has been discussed based on the cure and physical data and explained through the results based on high-performance liquid chromatography and a reaction mechanism. Synergistic activity is observed in all binary systems studied. The highest tensile strength is observed in the zinc (N-benzyl piperazino) dithiocarbamate-accelerated system at 3:6 mM ratios. In respect of tensile strength and modulus value, unsafe ZDMC can be successfully replaced by safe ZDCs in combination with thiazole group containing accelerator.

scholarly journals Composites from Thermoplastic Natural Rubber Reinforced Rubberwood Sawdust: Effects of Sawdust Size and Content on Thermal, Physical, and Mechanical Properties

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Chatree Homkhiew ◽  
Surasit Rawangwong ◽  
Worapong Boonchouytan ◽  
Wiriya Thongruang ◽  
Thanate Ratanawilai
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Natural Rubber ◽  
High Density Polyethylene ◽  
High Performance ◽  
Physical And Mechanical Properties ◽  
Modulus Of Rupture ◽  
Shore Hardness ◽  
Thermoplastic Natural Rubber ◽  
Plastic Content

The aim of this work is to investigate the effects of rubberwood sawdust (RWS) size and content as well as the ratio of natural rubber (NR)/high-density polyethylene (HDPE) blend on properties of RWS reinforced thermoplastic natural rubber (TPNR) composites. The addition of RWS about 30–50 wt% improved the modulus of the rupture and tensile strength of TPNR composites blending with NR/HDPE ratios of 60/40 and 50/50. TPNR composites reinforced with RWS 80 mesh yielded better tensile strength and modulus of rupture than the composites with RWS 40 mesh. The TPNR/RWS composites with larger HDPE content gave higher tensile, flexural, and Shore hardness properties and thermal stability as well as lower water absorption. The TPNR/RWS composites with larger plastic content were therefore suggested for applications requiring high performance of thermal, physical, and mechanical properties.

Influence of the Composition of Cement Mortars Modified by Lime or Polymers on the Mechanical Properties and Microstructure of Mortars

2013 ◽  
Vol 592-593 ◽  
pp. 647-650 ◽  
Author(s):  
Małgorzata Lenart
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Reinforced Concrete ◽  
Flexural Strength ◽  
Polyvinyl Alcohol ◽  
Polymer Composites ◽  
Adhesion Strength ◽  
Hardened Cement ◽  
Cement Mortars ◽  
Styrene Butadiene

Cement – polymer composites are nowadays widely used in repair systems not only in case of concrete or reinforced concrete constructions but also in masonry. Polymers addition for example already at 5% m.c. modifies the structure of the cement – polymer composite in a way that many of the mechanical properties such as flexural strength, tensile strength or adhesion to substrates are improved. The paper presents the results of tests such as flexural, compressive or adhesion strength to ceramic substrate of hardened cement mortars with different composition, as well as selected cement mortars modified by two polymers: polyvinyl alcohol and styrene – butadiene polymer dosed at 5 % m.c. Four types of cement mortars modified by lime (component used in historical constructions as well as in contemporary masonry mortars) are also examined for comparison.

Effect of Heat Setting Methods on Structures and Properties of High Strength Polyvinyl Alcohol Fibre

2015 ◽  
Vol 815 ◽  
pp. 643-648
Author(s):  
Yin Zhu ◽  
Jiong Xin Zhao
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Polyvinyl Alcohol ◽  
Setting Time ◽  
High Strength ◽  
Single Fibre ◽  
X Ray Diffraction ◽  
Heat Setting ◽  
Heat Treated ◽  
Setting Process

The effect of heat setting methods on the structures and mechanical properties of high strength polyvinyl alcohol (PVA) fibre is studied in this article. The microstructure and mechanical properties of heat treated PVA fibre is investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and single fibre electronic tensile strength tester. Results show that the heat setting method with constant tension is a good heat setting method which can largely enhance the tensile strength of PVA fibre. During the heat setting process, the mechanical properties of PVA fibre are greatly affected by the temperature, tension and setting time. When the temperature is 220°C, tension is 5cN/dtex and setting time is 90sec, the tensile strength of PVA fibre increases from 12.0cN/dtex to 16.4cN/dtex in compare with the PVA fibre without heat setting

The effect of large area graphene oxide (LAGO) nanosheets on the mechanical properties of polyvinyl alcohol

2016 ◽  
Vol 36 (4) ◽  
pp. 399-405 ◽  
Author(s):  
Khalid Nawaz ◽  
Muhammad Ayub ◽  
Noaman Ul-Haq ◽  
M.B. Khan ◽  
Muhammad Bilal Khan Niazi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Graphene Oxide ◽  
Polyvinyl Alcohol ◽  
Molecular Level ◽  
Large Area ◽  
Graphene Oxides ◽  
Elongation At Break ◽  
Graphene Oxide Sheets ◽  
Excellent Improvement

Abstract Large area graphene oxide sheets were synthesized, dispersed in water and used as nanofiller for mechanical improvement in terms of Young’s modulus and ultimate tensile strength (UTS) of polyvinyl alcohol (PVA) at low loading. The molecular level dispersion and interfacial interactions between the graphene oxides and polymeric matrix PVA were the real challenges. An excellent improvement in mechanical properties at 0.35 wt% loading was observed. Modulus improved from 1.58 GPa to 2.72 GPa (~71% improvement), UTS improved from 120 MPa to 197 MPa (~65% improvement), and in spite of these improvements, interestingly, there was no fall in elongation at break at this loading.

scholarly journals Characteristics of Recycled Polypropylene Fibers as an Addition to Concrete Fabrication Based on Portland Cement

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1827 ◽  
Author(s):  
Marcin Małek ◽  
Mateusz Jackowski ◽  
Waldemar Łasica ◽  
Marta Kadela
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
Polypropylene Fiber ◽  
Fiber Reinforced Concrete ◽  
Polypropylene Fibers ◽  
Split Tensile Strength ◽  
Recycled Polypropylene ◽  
Recycled Fibers

High-performance concrete has low tensile strength and brittle failure. In order to improve these properties of unreinforced concrete, the effects of adding recycled polypropylene fibers on the mechanical properties of concrete were investigated. The polypropylene fibers used were made from recycled plastic packaging for environmental reasons (long degradation time). The compressive, flexural and split tensile strengths after 1, 7, 14 and 28 days were tested. Moreover, the initial and final binding times were determined. This experimental work has included three different contents (0.5, 1.0 and 1.5 wt.% of cement) for two types of recycled polypropylene fibers. The addition of fibers improves the properties of concrete. The highest values of mechanical properties were obtained for concrete with 1.0% of polypropylene fibers for each type of fiber. The obtained effect of an increase in mechanical properties with the addition of recycled fibers compared to unreinforced concrete is unexpected and unparalleled for polypropylene fiber-reinforced concrete (69.7% and 39.4% increase in compressive strength for green polypropylene fiber (PPG) and white polypropylene fiber (PPW) respectively, 276.0% and 162.4% increase in flexural strength for PPG and PPW respectively, and 269.4% and 254.2% increase in split tensile strength for PPG and PPW respectively).

The Effect of Thermal Aging on Mechanical Properties and Morphological Properties of Thermoplastic Vulcanizates Based on Natural Rubber and Polystyrene

2020 ◽  
Vol 990 ◽  
pp. 262-266
Author(s):  
Prathumrat Nu-Yang ◽  
Atiwat Wiriya-Amornchai ◽  
Jaehoon Yoon ◽  
Chainat Saechau ◽  
Poom Rattanamusik
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Impact Strength ◽  
Natural Rubber ◽  
Thermal Aging ◽  
Morphological Properties ◽  
Vulcanized Rubber ◽  
Thermoplastic Vulcanizates ◽  
Internal Mixer ◽  
Processing Properties

Thermoplastic vulcanizates or TPVs is a type of materials exhibiting excellent properties between thermoplastic and elastomer by combining the characteristics of vulcanized rubber with the processing properties of thermoplastics. This research aims to study the effect of thermal aging on the morphology and mechanical properties of thermoplastic vulcanizates (TPVs) based on a mixture of natural rubber (NR) and polystyrene (PS). TPVs samples were prepared using the internal mixer at a mass ratio of NR/PS 70/30, 50/50, 30/70 and 0/100. Tensile properties and impact strength showed that when the amount of NR increased tends of impact strength and elongation at break increased but tends of tensile strength decreased. On the other hand, tends of tensile strength for thermal aging at 70°C for 3 days increased when the amount of PS increase. The blending ratio of NR / PS at 70/30 is the best. It gave a worthy increase from 19.94 MPa to be 25.56 MPa (28.18%).

PREPARATION OF CHAIN EXTENDED POLYURETHANE AND ITS COMPOSITES BASED ON CASTOR OIL AND COIR FIBER

2015 ◽  
Vol 1 (01) ◽  
pp. 67-70
Author(s):  
A. Malar Retna
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Castor Oil ◽  
High Performance ◽  
Chain Extender ◽  
Coir Fiber ◽  
Percentage Elongation ◽  
Polyurethane Composites ◽  
Performance Character ◽  
Scanning Electron

The chain extended polyurethane was synthesized by reacting castor oil based polyol with 4,4’-methylenebis(cyclohexyl) isocyanate and chain extender such as malonic acid. The composites have been fabricated by incorporating the coir fiber into the neat polyurethane. The polyurethane and its composites were characterized with respect to their mechanical properties such as hardness, tensile strength, percentage elongation and Young’s modulus. The morphology of neat polyurethane and its composites with coir fiber was studied using scanning electron microscope (SEM). These studies revealed the high performance character of the polyurethane composites with respect to the corresponding neat polyurethane.

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