scholarly journals Functionalizable coaxial PLLA/PDLA nanofibers with stereocomplexes at the internal interface

2021 ◽  
Author(s):  
Axel T. Neffe ◽  
Quanchao Zhang ◽  
Paul J. Hommes-Schattmann ◽  
Weiwei Wang ◽  
Xun Xu ◽  
...  
Keyword(s):  
Tensile Tests ◽  
Cell Adherence ◽  
Average Molar Mass ◽  
Internal Interface ◽  
Elongation At Break ◽  
Physiological Conditions ◽  
Young’S Moduli ◽  
Relaxation Effects ◽  
Lower Elongation ◽  
Coaxial Fibers

AbstractMultifunctionality of electrospun polylactic acid (PLA) nonwovens was generated by the morphological design of nanofibers. Coaxial fibers with a lower number average molar mass Mn PLLA core and a higher Mn PDLA shell form PDLA–PLLA stereocrystals at the interface, induced by annealing. In tensile tests under physiological conditions, the core–shell fibers with higher crystallinity (22% compared to 11–14%) had lower Young’s moduli E (9 ± 1 MPa) and lower elongation at break εb (26 ± 3%) than PDLA alone (E = 31 ± 9 MPa, εb = 80 ± 5%), which can be attributed to simultaneous crystallization and relaxation effects. Gelatin incorporated in the PDLA phase was presented on the outer surface providing a biointerface putatively favorable for cell adherence. Gelatin incorporation did not influence the crystallization behavior but slightly lowered Tg (60 → 54 °C). Employing exclusively polymers established in the clinic, multifunctionality was generated by design. Graphic abstract

Characterization of EVA Residues from the Shoe Industry and Post-Consumer Urban-Waste Polyethylenes

2005 ◽  
Vol 24 (3) ◽  
pp. 139-158 ◽  
Author(s):  
A.J. Zattera ◽  
O. Bianchi ◽  
R.V.B. Oliveira ◽  
L.B. Canto ◽  
C.A. Ferreira ◽  
...  
Keyword(s):  
Tensile Modulus ◽  
Urban Waste ◽  
Elongation At Break ◽  
Shoe Industry ◽  
Izod Impact ◽  
Lower Elongation ◽  
Mechanical Tensile ◽  
High Degree ◽  
Tga And Dsc

This paper presents a characterization of a crosslinked EVA residue (EVA-c) from expanded sheets used in the shoe industry and post-consumer urban-waste polyethylenes regarding their molecular (FTIR), mechanical (tensile and impact tests), morphological (SEM), thermal (DSC, TGA) and dynamic-mechanical (DMTA) properties. For comparison, the properties of the EVA-c and recycled polyethylenes are compared to respective virgin polymers. The recycled polyethylenes generally presented similar properties to the virgin ones. On the other hand, some EVA-c properties differed from virgin ones since it has a high degree of crosslinking and it therefore has a higher tensile modulus and lower elongation at break, notched Izod impact strength and hardness. Additionally, crosslinking was also found to modify the thermal properties (TGA and DSC) of EVA-c.

Temporary-Creep and Postcreep Properties of Aquaculture Netting Materials With UHMWPE Fibers

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Heidi Moe-Føre ◽  
Per Christian Endresen ◽  
Østen Jensen
Keyword(s):  
Creep Strain ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Tensile Tests ◽  
Test Results ◽  
Elongation At Break ◽  
Creep Properties ◽  
Mean Values ◽  
Ultrahigh Molecular Weight ◽  
Polyester Fibers ◽  
Uhmwpe Fibers

This paper presents test results on temporary-creep properties, recovery of strain postcreep and postcreep tensile properties of a Raschel knitted netting material with a combination of ultrahigh molecular weight polyethylene (UHMWPE) and polyester fibers. Specimens of the material were subjected to uniaxial loading over a period of 30 mins, at a constant creep target load of 10–90% of average tensile strength. The specimens were wet and tested in room temperature. The netting structure experienced creep strain with mean values in the range of 1.3–4.5%, increasing with increased creep target load. In addition, the netting experienced 2% creep strain during on-loading. The creep strains were elastic, while large proportions of the elongation accumulated during on-loading (structural strain of 8.8–27.8%) were long lasting and possibly permanent. Tensile tests showed that for the highest creep target load, strength, and elongation at break increased by 17%.

Recycled High Density Polyethylene / Natural Rubber / Chicken Feather Fibers (RHDPE/NR/CFF) Composites: The Effects of Fiber Loading and Benzyl Urea on Tensile Properties and Morphology Analysis

2013 ◽  
Vol 795 ◽  
pp. 582-586 ◽  
Author(s):  
M.I.M. Yazid ◽  
A.G. Supri ◽  
Z. Firuz ◽  
Luqman Musa
Keyword(s):  
Tensile Properties ◽  
High Density Polyethylene ◽  
Interfacial Adhesion ◽  
Chicken Feather ◽  
Rotor Speed ◽  
Elongation At Break ◽  
Fiber Loading ◽  
The Matrix ◽  
Feather Fibers ◽  
Lower Elongation

The effects of benzyl urea into RHDPE/NR/CFF composites with different fibers loading were studied. The composites were prepared using BrabenderPlasticorder at 160 °C with rotor speed of 50rpm. The composites were characterized in respect of their tensile properties and morphology. The results indicated that RHDPE/NR/CFF with benzyl urea composites show higher values of tensile strength, Youngs modulus, but lower elongation at break than RHDPE/NR/CFF composites. RHDPE/NR/CFF with benzyl urea composites gave a better interfacial adhesion between the matrix and the fiber than RHDPE/NR/CFF composites as evidence using SEM.

Effect of Compatibilizer Content on the Mechanical and Morphological Properties of PET/PP (70/30) Blends

2015 ◽  
Vol 735 ◽  
pp. 70-74
Author(s):  
Ibrahim Mohammed Inuwa ◽  
Azman Hassan ◽  
Sani Amril Samsudin
Keyword(s):  
Mechanical Properties ◽  
Triblock Copolymer ◽  
Standard Test ◽  
Morphological Properties ◽  
Screw Extruder ◽  
Elongation At Break ◽  
Young’S Moduli ◽  
Morphological Studies ◽  
Twin Screw ◽  
Pp Blends

This work investigates the effect of compatibilizer concentration on the mechanical properties of compatibilized polyethylene terephthalate (PET) /polypropylene (PP) blends. A blend containing 70 % (wt) PET, 30 % (wt) PP and 5 - 15 phr compatibilizers were compounded using counter rotating twin screw extruder and fabricated into standard test samples using injection molding. The compatibilizer used is styrene-ethylene-butylene-styrene grafted maleic anhydride triblock copolymer (SEBS-g-MAH). Morphological studies show that the particle size of the dispersed PP phase is dependent on the compatibilizer content up to 10 phr. Impact strength and elongation at break showed maximum values with the addition of 10 phr SEBS-g-MAH and a corresponding decrease in flexural and young’s moduli; and strengths.. Overall the mechanical properties of PET/PP blends depend on the control of the morphology of the blend and can be achieved by effective compatibilization using 10 phr SEBS-g-MAH.

Effect of Isophthalic Acid-Maleic Anhydride (IAMA) as a Compatibilizer on Tensile Properties and Swelling Behavior of Ethylene Vinyl Acetate (EVA)/Natural Rubber (NR)/Potash Feldspar Composites

2014 ◽  
Vol 679 ◽  
pp. 76-80
Author(s):  
S.H. Ho ◽  
A.Ghani Supri ◽  
Pei Leng Teh
Keyword(s):  
Maleic Anhydride ◽  
Natural Rubber ◽  
Tensile Properties ◽  
Vinyl Acetate ◽  
Ethylene Vinyl Acetate ◽  
Swelling Behavior ◽  
Rotor Speed ◽  
Potash Feldspar ◽  
Elongation At Break ◽  
Lower Elongation

The effect of isophathalic acid-maleic anhydride (IAMA) as a compatibilizer on the tensile properties and swelling behavior of ethylene vinyl acetate /natural rubber/ feldspar (EVA/NR/PF) composites were studied. The EVA/NR/PF composites with and without IAMA were prepared using Brabender Plasticoder at 160oC with 50rpm rotor speed. The results indicated that EVA/NR/PF/IAMA showed higher value of tensile strength and M100 but lower elongation at break and percentage mass swell compared to EVA/NR/PF composites.

Influence of the 2,2-Dimethylol Propionic Acid Content on the Structure-Properties of Waterborne Polyurethane

2012 ◽  
Vol 476-478 ◽  
pp. 2116-2121 ◽  
Author(s):  
Zheng Xiang Wang ◽  
Jian Long Wang ◽  
Li Zheng Gu
Keyword(s):  
Propionic Acid ◽  
Waterborne Polyurethane ◽  
Peel Strength ◽  
Scanning Calorimetry ◽  
Elongation At Break ◽  
Waterborne Polyurethanes ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Lower Elongation ◽  
Dimethylol Propionic Acid ◽  
Structure Properties

Abstract. Series waterborne polyurethane (WPU) dispersions with different 2,2-dimethylol propionic acid (DMPA) content were synthesized by the prepolymer method. Different configurations in the waterborne polyurethanes were obtained by varying the DMPA content. The structure-properties of the WPU dispersions were characterized by Fourier transformed infrared spectroscopy, Thermogravimetric analysis, differential scanning calorimetry, Zetasizer nano etc. The results indicated that the amount of urethane and urea groups (hard segment) increased in the structure of WPU chains with the increasing content of DMPA. In the meantime, the degree of micro-phase separation increased. On the other hand, as the content of DMPA increased, the particle size, the thermal stability and T-peel strength decreased. Moreover, the increased content of DMPA resulted in higher tensile strength and hardness, but lower elongation at break.

Production of a Green Composite: Mixture of Poly (Latic Acid) and Keratin Fibers from Chicken Feathers

2008 ◽  
Vol 47-50 ◽  
pp. 1225-1228 ◽  
Author(s):  
Yong Qing Zhao ◽  
Kin Tak Lau ◽  
Tao Liu ◽  
Sha Cheng ◽  
Pou Man Lam ◽  
...  
Keyword(s):  
Tensile Modulus ◽  
Tensile Tests ◽  
Poly Lactic Acid ◽  
Green Composite ◽  
Elongation At Break ◽  
Chicken Feathers ◽  
Composite Mixture ◽  
Keratin Fibers ◽  
Feather Fiber ◽  
First Time

A new biocomposite based on chicken feather fiber (CFF) and Poly (lactic acid) (PLA) was fabricated for the first time by melting compound methods. Its mechanical properties and fracture surfaces were investigated by using tensile tests and scanning electron microscopy (SEM), respectively. The results showed that the tensile modulus and elongation at break of PLA samples were improved by adding a small amount of CFF. The elongation at break of a CFF/PLA sample with 2 wt% of CFF was 56% higher than that of pure PLA. This may ascribe to the good adhesion and interactions between the CFF and PLA matrix.

Utilization of Maleic Anhydride Modified Ground EVA Waste in NBR Vulcanizates

2005 ◽  
Vol 78 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Bluma G. Soares ◽  
Ana C. O. Gomes ◽  
Viviane X. Moreira ◽  
Marcia G. Oliveira
Keyword(s):  
Tensile Strength ◽  
Maleic Anhydride ◽  
Mechanical Performance ◽  
Dynamic Testing ◽  
Good Resistance ◽  
Adhesion Promoter ◽  
Elongation At Break ◽  
Compression Set ◽  
Lower Elongation ◽  
Poly Ethylene

Abstract The influence of poly(ethylene-co-vinyl acetate) (EVA) waste (EVAW) on the rheological and mechanical properties of NBR vulcanizates compounds was studied. The optimum concentration of EVAW, which has presented higher ultimate tensile strength, was found to be 70 phr. In addition, the influence of EVAW modified with maleic anhydride as adhesion promoter was studied. Two distinct routes of modification with maleic anhydride were selected, originating a carboxylated EVA waste (EVAWCOOH) and an anhydride EVA waste (EVAWMA). An improvement of tensile strength and aging resistance was observed with the substitution of EVAW by EVAWCOOH or EVAWMA. A very good resistance to compression set has been achieved with the addition of EVAWCOOH. The improvement of mechanical performance was attributed to a better dispersion of EVAW along NBR matrix, promoted by the enhanced modified-waste polarity, which allowed a good interaction with polar NBR. The presence of anhydride group in functionalized EVAW resulted in the highest values of tensile strength but lower elongation at break and also lower values of tan delta obtained from dynamic testing. These behaviors have been attributed to an increase of crosslink density due to the reaction between zinc oxide and succinic pendant groups of EVAWMA.

Lignin reinforced, water resistant, and biodegradable cassava starch/PBAT sandwich composite pieces

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Liang Wang ◽  
Jun He ◽  
Qingdong Wang ◽  
Jing Zhang ◽  
Jie Feng
Keyword(s):  
Tensile Strength ◽  
Organic Fertilizer ◽  
Soil Health ◽  
Cost Effective ◽  
Cassava Starch ◽  
Sandwich Composite ◽  
Peanut Shell ◽  
Elongation At Break ◽  
Farm Production ◽  
Lower Elongation

Abstract Following the stipulation to replace nondegradable plastics with biodegradable materials in China, cost-effective and water-resistant packaging materials have become increasingly necessary. In this work, lignin reinforced thermoplastic cassava starch (TPS) pieces were prepared by filling glycerol and lignin powder into starch via a melt blending process and then being pressed into thin pieces. A mechanical properties test showed that following the addition of 3 wt% lignin, the tensile strength of the TPS piece was improved to 16.15 MPa from 3.71 MPa of the original TPS piece. The porous structures of the lignin powder tie the TPS macromolecular chains, induce higher crystallization, and thus provide higher tensile strength and lower elongation at break. After sandwiching two pieces of poly (butylene adipateco-terephthalate) (PBAT)/peanut shell powder composite thin film to each side of the TPS piece, the PBAT/TPS/PBAT sandwich gains excellent water resistance properties. However, as soon as the sandwich piece is cut into smaller ones, they absorb water quickly, implying such pieces can be biodegraded rapidly. These characteristics make it especially suitable for use in the preparation of cabinet waste bags, which are generally stirred into organic fertilizer with the cabinet waste. Slow degradation may negatively affect soil health and farm production.

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