Effect of Cold Drawing on Mechanical Properties of Biodegradable Fibers

Purpose Biodegradable polymers are currently gaining importance in several fields, because they allow mitigation of the impact on the environment related to disposal of traditional, nonbiodegradable polymers, as well as reducing the utilization of oil-based sources (when they also come from renewable resources). Fibers made of biodegradable polymers are of particular interest, though, it is not easy to obtain polymer fibers with suitable mechanical properties and to tailor these to the specific application. The main ways to tailor the mechanical properties of a given biodegradable polymer fiber are based on crystallinity and orientation control. However, crystallinity can only marginally be modified during processing, while orientation can be controlled, either during hot drawing or cold stretching. In this paper, a systematic investigation of the influence of cold stretching on the mechanical and thermomechanical properties of fibers prepared from different biodegradable polymer systems was carried out. Methods Rheological and thermal characterization helped in interpreting the orientation mechanisms, also on the basis of the molecular structure of the polymer systems. Results and conclusions It was found that cold drawing strongly improved the elastic modulus, tensile strength and thermomechanical resistance of the fibers, in comparison with hot-spun fibers. The elastic modulus showed higher increment rates in the biodegradable systems upon increasing the draw ratio.

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Possibilities of using biodegradable polymeric materials in the agricultural sector

Elektrotekhnologii i elektrooborudovanie v APK ◽

10.22314/2658-4859-2020-67-2-115-120 ◽

2020 ◽

Vol 67 (2) ◽

pp. 115-120

Author(s):

Raisa A. Alekhina ◽

Victoriya E. Slavkina ◽

Yuliya A. Lopatina

Keyword(s):

Mechanical Properties ◽

Biodegradable Polymers ◽

Biodegradable Polymer ◽

Agricultural Sector ◽

Polymeric Materials ◽

Polymer Materials ◽

Limiting Factors ◽

Research Purpose ◽

Biodegradable Materials ◽

Advantages And Disadvantages

The article presents options for recycling polymers. The use of biodegradable materials is promising. This is a special class of polymers that can decompose under aerobic or anaerobic conditions under the action of microorganisms or enzymes forming natural products such as carbon dioxide, nitrogen, water, biomass, and inorganic salts. (Research purpose) The research purpose is in reviewing biodegradable materials that can be used for the manufacture of products used in agriculture. (Materials and methods) The study are based on open information sources containing information about biodegradable materials. Research methods are collecting, studying and comparative analysis of information. (Results and discussion) The article presents the advantages and disadvantages of biodegradable materials, mechanical properties of the main groups of biodegradable polymers. The article provides a summary list of agricultural products that can be made from biodegradable polymer materials. It was found that products from the general group are widely used in agriculture. Authors have found that products from a special group can only be made from biodegradable polymers with a controlled decomposition period in the soil, their use contributes to increasing the productivity of crops. (Conclusions) It was found that biodegradable polymer materials, along with environmental safety, have mechanical properties that allow them producing products that do not carry significant loads during operation. We have shown that the creation of responsible products (machine parts) from biodegradable polymers requires an increase in their strength properties, which is achievable by creating composites based on them. It was found that the technological complexity of their manufacture and high cost are the limiting factors for the widespread use of biodegradable polymers at this stage.

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Numerical Studies of the Effects of Water Capsules on Self-Healing Efficiency and Mechanical Properties in Cementitious Materials

Advances in Materials Science and Engineering ◽

10.1155/2016/8271214 ◽

2016 ◽

Vol 2016 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Haoliang Huang ◽

Guang Ye

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Elastic Modulus ◽

Cementitious Materials ◽

Self Healing ◽

Negative Effects ◽

Numerical Studies ◽

Healing Efficiency ◽

The Impact ◽

Positive Effect

In this research, self-healing due to further hydration of unhydrated cement particles is taken as an example for investigating the effects of capsules on the self-healing efficiency and mechanical properties of cementitious materials. The efficiency of supply of water by using capsules as a function of capsule dosages and sizes was determined numerically. By knowing the amount of water supplied via capsules, the efficiency of self-healing due to further hydration of unhydrated cement was quantified. In addition, the impact of capsules on mechanical properties was investigated numerically. The amount of released water increases with the dosage of capsules at different slops as the size of capsules varies. Concerning the best efficiency of self-healing, the optimizing size of capsules is 6.5 mm for capsule dosages of 3%, 5%, and 7%, respectively. Both elastic modulus and tensile strength of cementitious materials decrease with the increase of capsule. The decreasing tendency of tensile strength is larger than that of elastic modulus. However, it was found that the increase of positive effect (the capacity of inducing self-healing) of capsules is larger than that of negative effects (decreasing mechanical properties) when the dosage of capsules increases.

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Renewable resources-based PTT [poly(trimethylene terephthalate)]/switchgrass fiber composites: The effect of compatibilization

Pure and Applied Chemistry ◽

10.1351/pac-con-12-04-05 ◽

2012 ◽

Vol 85 (3) ◽

pp. 521-532 ◽

Cited By ~ 3

Author(s):

Jeevan Prasad Reddy ◽

Manjusri Misra ◽

Amar Mohanty

Keyword(s):

Mechanical Properties ◽

Impact Strength ◽

Renewable Resources ◽

Melt Flow Index ◽

Mechanical Analysis ◽

Thermomechanical Properties ◽

Flow Index ◽

Methylene Diphenyl Diisocyanate ◽

Trimethylene Terephthalate ◽

The Impact

In this research, switchgrass (SG) fiber-reinforced poly(trimethylene terephthalate) (PTT) biocomposites were prepared by extrusion followed by injection molding machine. The methylene-diphenyl-diisocyanate-polybutadiene (MDIPB) prepolymer was used to enhance the impact strength of the biocomposites. In addition, the polymeric methylene-diphenyl-diisocyanate (PMDI) compatibilizer was used to enhance the mechanical properties of the composites. The effect of compatibilizer on mechanical, crystallization melting, thermomechanical, melt flow index (MFI), morphological, and thermal stability properties of the composites was studied. Thermomechanical properties of the biocomposites were studied by dynamic mechanical analysis (DMA). Scanning electron microscopy (SEM) was used to observe the interfacial adhesion between the fiber and matrix. The results showed that MDIPB and PMDI have a significant effect on the mechanical properties of the composites. The impact strength of MDIPB- and PMDI-compatibilized composites was increased by 87 % when compared to the uncompatibilized composite.

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Effects of microcrystalline cellulose on the mechanical properties of low-density polyethylene composites

Journal of Thermoplastic Composite Materials ◽

10.1177/0892705717753056 ◽

2018 ◽

Vol 32 (3) ◽

pp. 297-311 ◽

Cited By ~ 3

Author(s):

Yousef Ahmad Mubarak ◽

Raghda Talal Abdulsamad

Keyword(s):

Mechanical Properties ◽

Elastic Modulus ◽

Impact Strength ◽

Tensile Properties ◽

Microcrystalline Cellulose ◽

Weight Fraction ◽

Low Density Polyethylene ◽

Low Density ◽

Ldpe Composites ◽

The Impact

This work was intended to provide an understanding of the effect of microcrystalline cellulose (MCC) on the mechanical properties of low-density polyethylene (LDPE). The impact resistance and the tensile properties of low-density LDPE/MCC composites were investigated. The weight fraction of MCC was varied at (0, 0.5, 1, 2.5, 5, 10, 20, and 30 wt%). The obtained blends were then used to prepare the required tensile and impact testing samples by hot compression molding technique. It has been found that MCC has a strong influence on the mechanical properties of LDPE. At a low MCC weight fraction, there was a little improvement in the ultimate strength, fracture stress, and elongation at break, but at a high MCC weight fraction, the tensile properties were deteriorated and reduced significantly. The addition of 1 wt% MCC to LDPE enhanced the mentioned properties by 10, 25, and 6%, respectively. While at 30 wt% MCC, these properties were lowered by 36, 25, and 96%. The elastic modulus of LDPE composites was improved on all MCC weight fractions used in the study, at 20 wt% MCC, an increase in the elastic modulus by 12 folds was achieved. On the other hand and compared with the impact strength of pure LDPE, the addition of MCC particles enhanced the impact strength, the highest value obtained was for LDPE composites filled with 10 wt% MCC where the impact strength enhanced by two folds.

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Effect of degree of substitution on the mechanical and thermomechanical properties of lauroyl cellulose ester films

e-Polymers ◽

10.1515/epoly.2006.6.1.895 ◽

2006 ◽

Vol 6 (1) ◽

Cited By ~ 1

Author(s):

Nicolas Joly ◽

Patrick Martin ◽

Luc Liénard ◽

Delphine Rutot ◽

Fabrice Stassin ◽

...

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Elastic Modulus ◽

Mechanical Analysis ◽

Thermomechanical Properties ◽

Degree Of Substitution ◽

Cellulose Ester ◽

Plastic Films ◽

Ester Formation ◽

Homogeneous Media

AbstractCellulose-based plastic films were prepared in homogeneous media with a range of lauroyl fatty acid attachments by ester formation, expressed as the degree of substitution (DS). The esters were cast to form films and their mechanical properties studied. This study showed a surprising relationship between DS and elastic modulus as well as DS and tensile strength, where a peak was observed at DS 2.4. The unexpected variation of static elastic modulus (E) was confirmed by dynamic mechanical analysis (DMA) and this trend was also observed for glass transition temperature (Tg). These results are discussed in relation to sample cohesion.

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Sub-surface mechanical properties and sub-surface creep behavior of wood-plastic composites reinforced by organoclay

Science and Engineering of Composite Materials ◽

10.1515/secm-2016-0291 ◽

2019 ◽

Vol 26 (1) ◽

pp. 114-121

Author(s):

Sumit Manohar Yadav ◽

Kamal Bin Yusoh

Keyword(s):

Mechanical Properties ◽

Elastic Modulus ◽

Creep Behavior ◽

Creep Resistance ◽

Early Stage ◽

Viscoelastic Model ◽

Wood Plastic Composites ◽

Plastic Composites ◽

Surface Creep ◽

The Impact

AbstractWood-plastic composites (WPC) were manufactured from polypropylene, wood flour, maleic anhydride grafted polypropylene and organoclay. The sub-surface mechanical properties and the sub-surface creep behavior of the organoclay-based WPC were examined by the nanoindentation technique. The results showed that the hardness, elastic modulus and creep resistance of the WPC enhanced with the loading of C20 organoclay. This enhancement was subject to the organoclay content and the dispersion of organoclay in the polymer matrix. The hardness, elastic modulus and creep resistance of WPC with 1 wt% organoclay content enhanced by approximately 36%, 41% and 17%, respectively, in contrast with WPC without organoclay. To study the impact of organoclay content on the creep performance of WPC, a viscoelastic model was actualized. The results demonstrated that the model was in good agreement with the experimental information. Reinforcement of organoclay prompts expansion in elastic deformation and instigates a higher initial displacement at the early stage of creep.

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Effect of Dry-Wet Cycling on the Mechanical Properties of Rocks: A Laboratory-Scale Experimental Study

Processes ◽

10.3390/pr6100199 ◽

2018 ◽

Vol 6 (10) ◽

pp. 199 ◽

Cited By ~ 11

Author(s):

Xiaojie Yang ◽

Jiamin Wang ◽

Dinggui Hou ◽

Chun Zhu ◽

Manchao He

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Elastic Modulus ◽

Uniaxial Compressive Strength ◽

Open Pit ◽

Rock Surface ◽

Periodic Action ◽

Rock Interaction ◽

The Impact ◽

Water Rock Interaction

Taking Nanfen open-pit iron mine in Liaoning Province as the engineering background, this study analyzes the effect of water-rock circulation on the mechanical properties of rock through a combination of macro-mechanical experiments and microstructure tests in the laboratory. Uniaxial compression experiments and acoustic wave tests are used to determine the degradation law of the mechanical properties of chlorite under the periodic action of water. The experimental results show that dry-wet cycles have a continuous and gradual effect on the rock sampled: Its uniaxial compressive strength, elastic modulus, and acoustic velocity all decrease gradually with an increase in the number of cycles. After 15 wet-dry cycles, the uniaxial compressive strength and elastic modulus of the rock decreased by 34.21% and 44.63%, respectively. Electron microscope scans of the rock indicate that the particle size, characteristics, and pore distribution at the rock surface had changed significantly after water-rock interaction. Finally, a drainage system and sliding force monitoring devices have been arranged at the mine site that can effectively reduce the impact of water-rock interaction on the stability of the mine. This combination of macro-experiments and micro-analysis allowed the weakening effect of dry-wet cycles on slope rock to be studied quantitatively, providing a theoretical reference for stability evaluation in geotechnical engineering.

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Mechanical Properties of Thermoplastic Polymers for Aligner Manufacturing: In Vitro Study

Dentistry Journal ◽

10.3390/dj8020047 ◽

2020 ◽

Vol 8 (2) ◽

pp. 47 ◽

Cited By ~ 1

Author(s):

Francesco Tamburrino ◽

Vincenzo D’Antò ◽

Rosaria Bucci ◽

Giulio Alessandri-Bonetti ◽

Sandro Barone ◽

...

Keyword(s):

Mechanical Properties ◽

Elastic Modulus ◽

Yield Stress ◽

Artificial Saliva ◽

In Vitro Study ◽

Tensile Tests ◽

Operating Conditions ◽

Thermoplastic Polymers ◽

The Impact

The use of metal-free thermoplastic materials plays a key role in the orthodontic digital workflow due to the increasing demand for clear aligner treatments. Three thermoplastic polymers commonly used to fabricate clear aligners, namely Duran®, Biolon® and Zendura®, were investigated to evaluate the effect of thermoforming (T.), storage in artificial saliva (S.A.S.) and their combination on their mechanical properties. Elastic modulus and yield stress of the specimens were characterized. Each material was characterized for each condition through tensile tests (ISO527-1). The results showed that thermoforming does not lead to a significant decrease in yield stress, except for Zendura® that showed about a 30% decrease. An increase of the elastic modulus of Duran® and Zendura®, instead, was observed after thermoforming. The same increase was noticed for the yield stress of Duran®. For S.A.S. specimens, the elastic modulus generally decreases compared to supplier condition (A.S.) and simply thermoformed material. A decrease of yield stress, instead, is significant for Zendura®. The results demonstrated that the impact of the operating conditions on the mechanical properties can vary according to the specific polymer. To design reliable and effective orthodontic treatments, the materials should be selected after their mechanical properties are characterized in the simulated intraoral environment.

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Elucidating nanoscale mechanical properties of diabetic human adipose tissue using atomic force microscopy

Scientific Reports ◽

10.1038/s41598-020-77498-w ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

J. K. Wenderott ◽

Carmen G. Flesher ◽

Nicki A. Baker ◽

Christopher K. Neeley ◽

Oliver A. Varban ◽

...

Keyword(s):

Mechanical Properties ◽

Metabolic Disease ◽

Atomic Force Microscopy ◽

Adipose Tissue ◽

Elastic Modulus ◽

Tissue Mechanics ◽

Health Concern ◽

Force Microscopy ◽

Atomic Force ◽

The Impact

AbstractObesity-related type 2 diabetes (DM) is a major public health concern. Adipose tissue metabolic dysfunction, including fibrosis, plays a central role in DM pathogenesis. Obesity is associated with changes in adipose tissue extracellular matrix (ECM), but the impact of these changes on adipose tissue mechanics and their role in metabolic disease is poorly defined. This study utilized atomic force microscopy (AFM) to quantify difference in elasticity between human DM and non-diabetic (NDM) visceral adipose tissue. The mean elastic modulus of DM adipose tissue was twice that of NDM adipose tissue (11.50 kPa vs. 4.48 kPa) to a 95% confidence level, with significant variability in elasticity of DM compared to NDM adipose tissue. Histologic and chemical measures of fibrosis revealed increased hydroxyproline content in DM adipose tissue, but no difference in Sirius Red staining between DM and NDM tissues. These findings support the hypothesis that fibrosis, evidenced by increased elastic modulus, is enhanced in DM adipose tissue, and suggest that measures of tissue mechanics may better resolve disease-specific differences in adipose tissue fibrosis compared with histologic measures. These data demonstrate the power of AFM nanoindentation to probe tissue mechanics, and delineate the impact of metabolic disease on the mechanical properties of adipose tissue.

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Effect of Mineral Fillers on the Mechanical Properties of Commercially Available Biodegradable Polymers

Polymers ◽

10.3390/polym13030394 ◽

2021 ◽

Vol 13 (3) ◽

pp. 394

Author(s):

Wouter Post ◽

Lambertus J. Kuijpers ◽

Martin Zijlstra ◽

Maarten van der Zee ◽

Karin Molenveld

Keyword(s):

Mechanical Properties ◽

Biodegradable Polymers ◽

Plastic Material ◽

Impact Resistance ◽

Plastic Materials ◽

The Matrix ◽

Polybutylene Succinate ◽

Mineral Fillers ◽

The Impact ◽

Plastic Products

In the successful transition towards a circular materials economy, the implementation of biobased and biodegradable plastics is a major prerequisite. To prevent the accumulation of plastic material in the open environment, plastic products should be both recyclable and biodegradable. Research and development actions in the past few decades have led to the commercial availability of a number of polymers that fulfil both end-of-life routes. However, these biobased and biodegradable polymers typically have mechanical properties that are not on par with the non-biodegradable plastic products they intend to replace. This can be improved using particulate mineral fillers such as talc, calcium carbonate, kaolin, and mica. This study shows that composites thereof with polybutylene succinate (PBS), polyhydroxybutyrate-hexanoate (PHBH), polybutylene succinate adipate (PBSA), and polybutylene adipate terephthalate (PBAT) as matrix polymers result in plastic materials with mechanical properties ranging from tough elastic towards strong and rigid. It is demonstrated that the balance between the Young’s modulus and the impact resistance for this set of polymer composites is subtle, but a select number of investigated compositions yield a combination of industrially relevant mechanical characteristics. Finally, it is shown that the inclusion of mineral fillers into biodegradable polymers does not negate the microbial disintegration of these polymers, although the nature of the filler does affect the biodegradation rate of the matrix polymer.

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