scholarly journals Toughening Modification of Polylactic Acid by Thermoplastic Silicone Polyurethane Elastomer

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1953
Author(s):  
Mingtao Sun ◽  
Shuang Huang ◽  
Muhuo Yu ◽  
Keqing Han

The melt blending of polylactic acid (PLA) and thermoplastic silicone polyurethane (TPSiU) elastomer was performed to toughen PLA. The molecular structure, crystallization, thermal properties, compatibility, mechanical properties and rheological properties of the PLA/TPSiU blends of different mass ratios (100/0, 95/5, 90/10, 85/15 and 80/20) were investigated. The results showed that TPSiU was effectively blended into PLA, but no chemical reaction occurred. The addition of TPSiU had no obvious effect on the glass transition temperature and melting temperature of PLA, but slightly reduced the crystallinity of PLA. The morphology and dynamic mechanical analysis results demonstrated the poor thermodynamic compatibility between PLA and TPSiU. Rheological behavior studies showed that PLA/TPSiU melt was typically pseudoplastic fluid. As the content of TPSiU increased, the apparent viscosity of PLA/TPSiU blends showed a trend of rising first and then falling. The addition of TPSiU had a significant effect on the mechanical properties of PLA/TPSiU blends. When the content of TPSiU was 15 wt%, the elongation at break of the PLA/TPSiU blend reached 22.3% (5.0 times that of pure PLA), and the impact strength reached 19.3 kJ/m2 (4.9 times that of pure PLA), suggesting the favorable toughening effect.

2014 ◽  
Vol 703 ◽  
pp. 45-50
Author(s):  
Chao Wang ◽  
Ying Chun Li ◽  
Guo Sheng Hu

The blends of Nylon 6/Acrylonitrile-Butadiene-Styrene (ABS) with styrene-maleic anhydride (SMA) was prepared by melt blending as the compatilizer. Mechanical properties, dynamic mechanical analysis (DMA) and fracture appearances were determined. It was found that the impact and tensile strength firstly increased and then decreased along with the increase of the SMA content. The properties reached maximum values when the content of SMA was 1.5%. The results of DMA and scanning electron microscope (SEM) indicated that the addition of SMA can effectively enhance the compatibility of Nylon 6 and ABS. Key words: Nylon 6, ABS, SMA, blends, modification


2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Yueyun Zhou ◽  
Lifa Luo ◽  
Wenyong Liu ◽  
Guangsheng Zeng ◽  
Yi Chen

To overcome the poor toughness of PC/PLA blends due to the intrinsic properties of materials and poor compatibility, thermoplastic urethane (TPU) was added to PC/PLA blends as a toughener; meantime, catalyst di-n-butyltin oxide (DBTO) was also added for catalyzing transesterification of components in order to modify the compatibility of blends. The mechanical, thermal, and rheological properties of blends were investigated systematically. The results showed that the addition of TPU improves the toughness of PC/PLA blends significantly, with the increase of TPU, the elongation at break increases considerably, and the impact strength increases firstly and then falls, while the tensile strength decreases significantly and the blends exhibit a typical plastic fracture behavior. Meantime, TPU is conducive to the crystallinity of PLA in blends which is inhibited seriously by PC and damages the thermal stability of blends slightly. Moreover, the increased TPU makes the apparent viscosity of blends melt decrease due to the well melt fluidity of TPU; the melt is closer to the pseudoplasticity melt. Remarkably, the transesterification between the components improves the compatibility of blends significantly, and more uniform structure results in a higher crystallinity and better mechanical properties.


2013 ◽  
Vol 781-784 ◽  
pp. 390-394
Author(s):  
Xiao Li Song ◽  
Ying Chen ◽  
Yu Zhi Xu ◽  
Chun Peng Wang

Polyacrylate microsphere with different core/shell ratio (mass ratio) were prepared by semi-continuous seed emulsion copolymerization using butyl acrylate (BA) and methyl methacrylate (MMA) as main monomers,which were used to toughen polylactic acid (PLA) after drying. The effect of core/shell ratio of polyacrylate toughening agent (ACR) on mechanical properties of PLA was studied. The results showed that when adding 8wt%ACR, the impact strength and elongation at break of PLA were both first increased and then decreased as increasing of core/shell ratio, while the tensile strength loss of PLA was little changed. It is found that the impact strength was increased about 24% than that of neat PLA as well as the elongation at break was increased from 2% to 12% when the ratio was 7/3, which was the best ratio.


2011 ◽  
Vol 239-242 ◽  
pp. 3146-3149
Author(s):  
Jia Min Zhang ◽  
Ming Yi Zhu ◽  
Zhao Xun Lian

The impacts of multi-monomers melt grafting blends of maleic anhydride(MAH) and Styrene (St) on the crystallization behavior, morphology and mechanical properties of PA1010/ABS/PP blends were studied through the methods of SEM,themal analysis, mechanical properties analysis. The results showed that the graft copolymer generated in situ by the anhydride groups of g-PP and the amino end of PA1010 reduced the interfacial tension of blends efficiently, and the interaction of the styrene groups of the graft copolymer and ABS is helpful to improve the compatibility of three components during the melt blending process. The size of dispersed phase in blends is reduced obviously and the mechanical properties have a great improvement when the percentage of g-PP in the PA1010/ABS/PP blends increases to 10%. The tensile strength of the compatibilized PA1010/ABS/PP blends is improved by 11.7%,and the impact strength and elongation at break are increased 4 times and 4.9 times, respectively.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3140
Author(s):  
Kamil Dydek ◽  
Anna Boczkowska ◽  
Rafał Kozera ◽  
Paweł Durałek ◽  
Łukasz Sarniak ◽  
...  

The main aim of this work was the investigation of the possibility of replacing the heavy metallic meshes applied onto the composite structure in airplanes for lightning strike protection with a thin film of Tuball single-wall carbon nanotubes in the form of ultra-light, conductive paper. The Tuball paper studied contained 75 wt% or 90 wt% of carbon nanotubes and was applied on the top of carbon fibre reinforced polymer before fabrication of flat panels. First, the electrical conductivity, impact resistance and thermo-mechanical properties of modified laminates were measured and compared with the reference values. Then, flat panels with selected Tuball paper, expanded copper foil and reference panels were fabricated for lightning strike tests. The effectiveness of lightning strike protection was evaluated by using the ultrasonic phased-array technique. It was found that the introduction of Tuball paper on the laminates surface improved both the surface and the volume electrical conductivity by 8800% and 300%, respectively. The impact resistance was tested in two directions, perpendicular and parallel to the carbon fibres, and the values increased by 9.8% and 44%, respectively. The dynamic thermo-mechanical analysis showed higher stiffness and a slight increase in glass transition temperature of the modified laminates. Ultrasonic investigation after lightning strike tests showed that the effectiveness of Tuball paper is comparable to expanded copper foil.


Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1242
Author(s):  
Olga Mysiukiewicz ◽  
Paulina Kosmela ◽  
Mateusz Barczewski ◽  
Aleksander Hejna

Investigations related to polymer/metal composites are often limited to the analysis of the electrical and thermal conductivity of the materials. The presented study aims to analyze the impact of aluminum (Al) filler content (from 1 to 20 wt%) on the rarely investigated properties of composites based on the high-density polyethylene (HDPE) matrix. The crystalline structure, rheological (melt flow index and oscillatory rheometry), thermal (differential scanning calorimetry), as well as static (tensile tests, hardness, rebound resilience) and dynamic (dynamical mechanical analysis) mechanical properties of composites were investigated. The incorporation of 1 and 2 wt% of aluminum filler resulted in small enhancements of mechanical properties, while loadings of 5 and 10 wt% provided materials with a similar performance to neat HDPE. Such results were supported by the lack of disturbances in the rheological behavior of composites. The presented results indicate that a significant content of aluminum filler may be introduced into the HDPE matrix without additional pre-treatment and does not cause the deterioration of composites’ performance, which should be considered beneficial when engineering PE/metal composites.


Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2378
Author(s):  
Mertol Tüfekci ◽  
Sevgi Güneş Durak ◽  
İnci Pir ◽  
Türkan Ormancı Acar ◽  
Güler Türkoğlu Demirkol ◽  
...  

To investigate the effect of polyvinylpyrrolidone (PVP) addition and consequently porosity, two different sets of membranes are manufactured, since PVP is a widely used poring agent which has an impact on the mechanical properties of the membrane material. The first set (PAN 1) includes polyacrylonitrile (PAN) and the necessary solvent while the second set (PAN 2) is made of PAN and PVP. These membranes are put through several characterisation processes including tensile testing. The obtained data are used to model the static behaviour of the membranes with different geometries but similar loading and boundary conditions that represent their operating conditions. This modelling process is undertaken by using the finite element method. The main idea is to investigate how geometry affects the load-carrying capacity of the membranes. Alongside membrane modelling, their materials are modelled with representative elements with hexagonal and rectangular pore arrays (RE) to understand the impact of porosity on the mechanical properties. Exploring the results, the best geometry is found as the elliptic membrane with the aspect ratio 4 and the better RE as the hexagonal array which can predict the elastic properties with an approximate error of 12%.


2012 ◽  
Vol 32 (6-7) ◽  
pp. 435-444 ◽  
Author(s):  
Hsin-Tzu Liao ◽  
Chin-San Wu

Abstract Melt blending of polylactide (PLA), poly(ε-caprolactone) (PCL), and wood flour (WF) was performed in an effort to overcome the major drawbacks (brittleness and high price) of PLA. In addition, the acrylic acid (AA)-grafted PLA70PCL30 (PLA70PCL30-g-AA) was used as the alternative for the preparation of ternary blends to improve the compatibility and the dispersability of WF within the PLA70PCL30 matrix. As expected, PCL improved the elongation at break and the toughness of PLA but decreased the tensile strength and modulus. Because the hydrophilic WF is dispersed physically in the hydrophobic PLA70PCL30 matrix, as the result of Fourier transform infrared analysis, the mechanical properties of PLA70PCL30 became noticeably worse when it was blended with WF. This problem was successfully conquered by using PLA70PCL30-g-AA to replace PLA70PCL30 due to the formation of an ester carbonyl group between PLA70PCL30-g-AA and WF. Furthermore, the PLA70PCL30-g-AA/WF blend provided a plateau tensile strength at break when the WF content was up to 50 wt%. PLA70PCL30/WF exhibited a tensile strength at break of approximately 3–25 MPa more than PLA70PCL30-g-AA/WF. By using p-cresol and tyrosinase, the enzymatic biodegradable test showed that PLA70PCL30-g-AA is somewhat more biodegradable than PLA70PCL30 because the former has better water absorption. After 16 weeks, the weight loss of the PLA70PCL30/WF (50 wt%) composite was >80%. PLA70PCL30-g-AA/WF exhibited a weight loss of approximately 1–12 wt% more than PLA70PCL30-g-AA/WF. It was also found that the addition of WF to PLA70PCL30 or PLA70PCL30-g-AA decreased the crystallinity of PLA and PCL in PLA70PCL30 or PLA70PCL30-g-AA and then increased their biodegradable property.


2021 ◽  
pp. 096739112110576
Author(s):  
Ying Zhou ◽  
Can Chen ◽  
Lan Xie ◽  
Xiaolang Chen ◽  
Guangqiang Xiao ◽  
...  

In this work, novel plasticizing biodegradable poly (lactic acid) (PLA) composites were prepared by melt blending of jute and tung oil anhydride (TOA), and the physical and mechanical properties of PLA/jute/TOA composites were tested and characterized. The impact strength of PLA/jute/TOA composites significantly increases with increasing the content of TOA. The SEM images of fracture surface of PLA/jute/TOA composites become rough after the incorporation of TOA. In addition, TOA changes the crystallization temperature and decomposition process of PLA/jute/TOA composites. With increasing the amount of TOA, the value of storage modulus (E′) of PLA/jute/TOA composites gradually increases. The complex viscosity (η*) values for all samples reduce obviously with increasing the frequency, which means that the pure PLA and PLA/jute/TOA composites is typical pseudoplastic fluid. This is attributed to the formation of crosslinking, which restricts the deformation of the composites.


2012 ◽  
Vol 85 (3) ◽  
pp. 521-532 ◽  
Author(s):  
Jeevan Prasad Reddy ◽  
Manjusri Misra ◽  
Amar Mohanty

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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