scholarly journals Morphology, Thermo-Mechanical Properties and Biodegradibility of PCL/PLA Blends Reactively Compatibilized by Different Organic Peroxides

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4205
Author(s):  
Marta Przybysz-Romatowska ◽  
Mateusz Barczewski ◽  
Szymon Mania ◽  
Agnieszka Tercjak ◽  
Józef Haponiuk ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Tests ◽  
Organic Peroxide ◽  
Poly Lactic Acid ◽  
Organic Peroxides ◽  
Reactive Blending ◽  
Scanning Calorimetry ◽  
The Sustainable Development ◽  
Tert Butyl ◽  
Reactive Modification

Reactive blending is a promising approach for the sustainable development of bio-based polymer blends and composites, which currently is gaining more and more attention. In this paper, biodegradable blends based on poly(ε-caprolactone) (PCL) and poly(lactic acid) (PLA) were prepared via reactive blending performed in an internal mixer. The PCL and PLA content varied in a ratio of 70/30 and 55/45. Reactive modification of PCL/PLA via liquid organic peroxides (OP) including 0.5 wt.% of tert-butyl cumyl peroxide (BU), 2,5-dimethyl-2,5-di-(tert-butylperoxy)-hexane (HX), and tert-butyl peroxybenzoate (PB) is reported. The materials were characterized by rotational rheometer, atomic force microscopy (AFM), thermogravimetry (TGA), differential scanning calorimetry (DSC), tensile tests and biodegradability tests. It was found that the application of peroxides improves the miscibility between PCL and PLA resulted in enhanced mechanical properties and more uniform morphology. Moreover, it was observed that the biodegradation rate of PCL/PLA blends reactively compatibilized was lower comparing to unmodified samples and strongly dependent on the blend ratio and peroxide structure. The presented results confirmed that reactive blending supported by organic peroxide is a promising approach for tailoring novel biodegradable polymeric systems with controllable biodegradation rates.

Synthesis and properties of soluble polyimides containing tert-butyl, ether linkages, and triphenylmethane units

2020 ◽  
Vol 32 (8) ◽  
pp. 924-932
Author(s):  
Zhuwei Qin ◽  
Suyun Lv ◽  
Yixuan Wu ◽  
Cong Wang ◽  
Siyu Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Diphenyl Ether ◽  
Tensile Tests ◽  
Nitrogen Atmosphere ◽  
Step Method ◽  
Scanning Calorimetry ◽  
Butyl Ether ◽  
Ether Linkage ◽  
Good Thermal Stability ◽  
Tert Butyl

A molecular theory design was carried out to synthesize a diamine monomer 1-(4-tert-butylphenyl)-1,1-bis[4-(4-aminophenoxy)] phenylethane containing tert-butyl, ether linkage, and triphenylmethane units. Then it was polymerized with several commercial aromatic dianhydrides, including diphenyl hexafluoroisopropylidene tetraic acid dianhydride (6FDA), diphenyl ether tetracarboxylic dianhydride (ODPA), biphenyltetracarboxylic dianhydride (BPDA), and benzophenone tetraacid dianhydride (BTDA), via the conventional two-step method to afford a series of aromatic polyimides (PIs). The structure and properties of the polymer were characterized by Fourier transform infrared (FTIR) spectroscopy, solubility test, thermogravimetric analysis, differential scanning calorimetry, ultraviolet–visible spectroscopy, and tensile tests. The results showed that there were characteristic peaks of PI around 1776, 1720, and 1378 cm−1 in the FTIR spectra; 6FDA-, ODPA-, and BPDA-based PI are easily soluble in N-methylpyrrolidone (NMP), concentrated sulfuric acid, N,N-dimethylacetamide (DMAc), pyridine, Tetrahydrofuran (THF), Trichloromethane (CHCl3), and other common organic solvents showing excellent solubility. In a nitrogen atmosphere, the glass transition temperature of the PI films are between 246°C and 275°C, the temperature of 5% weight loss is above 501°C, and the residual mass fraction at 750°C is 53–61%. The mechanical properties range from 67.2 MPa to 88.6 MPa. In addition to the BTDA-based PI film, the other three types of PI have good transparency. The simultaneous introduction of tert-butyl, ether linkages, and triphenylmethane units has a synergistic effect, which greatly improves the solubility of PI and maintains good thermal stability, mechanical properties, and optical properties of PI at the same time.

scholarly journals Application of Melt-Blown Poly(lactic acid) Fibres in Self-Reinforced Composites

Polymers ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 766 ◽  
Author(s):  
Dániel Vadas ◽  
Dávid Kmetykó ◽  
György Marosi ◽  
Katalin Bocz
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Fold Increase ◽  
Tensile Tests ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Static Tensile ◽  
Micrometer Size ◽  
Nonwoven Mats

The aim of our research was to produce poly(lactic acid) (PLA) fibres with diameters in the micrometer size range, serving as the reinforcing phase in self-reinforced (SR) PLA composites. Nonwoven PLA mats were manufactured by solvent-free melt-blowing technology. Three types of PLA differing in d-lactide content were processed with a productivity as high as 36 g/h. The crystallinity of the PLA microfibres was enhanced by thermal annealing. A 2–3-fold increase in the degree of crystallinity was obtained, as measured by differential scanning calorimetry (DSC). Fibre diameters between 2–14 µm were revealed by scanning electron microscopy (SEM). Static tensile tests were performed on the nonwoven mats, showing the reduced moduli of the annealed fibres due the amorphous relaxation. The PLA mats were processed via the hot compaction technique and formed into SR–PLA composites. The morphological and mechanical properties of the obtained microstructural composites were comprehensively studied. Composites prepared from annealed, thermally more stable PLA nonwoven mats showed superior mechanical properties; the tensile strength improved by 47% due to the higher residual fibre content.

Thermal Properties of Poly(Lactic Acid) Modified Poly(3-Hydroxybutyrate-co-4-Hydroxbutyrate)

2016 ◽  
Vol 852 ◽  
pp. 677-685
Author(s):  
Mei Li ◽  
Zhi Qiang Li ◽  
Wei Shao
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Thermal Properties ◽  
Tensile Tests ◽  
Poly Lactic Acid ◽  
Flow Properties ◽  
Scanning Calorimetry ◽  
Melt Flow Rate ◽  
Elongation At Break ◽  
Good Flow

The thermal properties of poly (lactic acid)[PLA] modified poly (3 –hydroxybutyrate –co-4 -hydroxbutyrate) [P(3HB-co-4HB)], prepared by melt blending with different blending ratios were investigated by differential scanning calorimetry [DSC], thermogravimetry [TGA], melt flow rate [MFR] and tensile test measurements, and scanning electron microscopy [SEM]. The DSC tests showed that the glass transition temperature, Tg, of P(3HB-co-4HB) increased from-7°C to 56°C when mixed with 50% to 67% of PLA. A decrease in crystallization temperature, Tc, of P(3HB-co-4HB) broadened the melting interval. The MFR tests indicated the blends had good flow properties and the variation of the PLA content had little effect on the flow properties. The tensile tests showed that PLA improved the mechanical properties of P(3HB-co-4HB), including the tensile strength and elongation at break. The blends had the best mechanical properties when the percentage of PLA was 64%.

scholarly journals Mechanical, Thermal and Rheological Properties of Polyethylene-Based Composites Filled with Micrometric Aluminum Powder

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1242
Author(s):  
Olga Mysiukiewicz ◽  
Paulina Kosmela ◽  
Mateusz Barczewski ◽  
Aleksander Hejna
Keyword(s):  
Mechanical Properties ◽  
Melt Flow Index ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Flow Index ◽  
Scanning Calorimetry ◽  
Metal Composites ◽  
Pre Treatment ◽  
The Impact ◽  
Properties Of Composites

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.

Enhancing the Thermal and Mechanical Characteristics of Polyvinyl Alcohol (PVA)-Hemp Protein Particles (HPP) Composites

2021 ◽  
Vol 36 (2) ◽  
pp. 137-143
Author(s):  
S. A. Awad
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperatures ◽  
Composite Films ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Decomposition Temperature ◽  
Scanning Calorimetry ◽  
Solution Casting Method ◽  
Protein Particles

Abstract This paper aims to describe the thermal, mechanical, and surface properties of a PVA/HPP blend whereby the film was prepared using a solution casting method. The improvements in thermal and mechanical properties of HPP-based PVA composites were investigated. The characterization of pure PVA and PVA composite films included tensile tests, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The results of TGA and DSC indicated that the addition of HPP increased the thermal decomposition temperature of the composites. Mechanical properties are significantly improved in PVA/HPP composites. The thermal stability of the PVA composite increased with the increase of HPP filler content. The tensile strength increased from 15.74 ± 0.72 MPa to 27.54 ± 0.45 MPa and the Young’s modulus increased from 282.51 ± 20.56 MPa to 988.69 ± 42.64 MPa for the 12 wt% HPP doped sample. Dynamic mechanical analysis (DMA) revealed that at elevated temperatures, enhanced mechanical properties because of the presence of HPP was even more noticeable. Morphological observations displayed no signs of agglomeration of HPP fillers even in composites with high HPP loading.

Initial properties and ageing behaviour of pineapple leaf and palm fibre as reinforcement for polypropylene

2016 ◽  
Vol 30 (2) ◽  
pp. 174-195 ◽  
Author(s):  
Rungsima Chollakup ◽  
Haroutioun Askanian ◽  
Florence Delor-Jestin
Keyword(s):  
Mechanical Properties ◽  
Cost Effective ◽  
Tensile Tests ◽  
Natural Fibre ◽  
Thermal Ageing ◽  
Second Step ◽  
Scanning Calorimetry ◽  
Ultraviolet Exposure ◽  
Palm Fibre

In the furniture, automotive and contruction industries, there is increased demand for cost-effective and lightweight biocomposites. The objective of this work was to develop new natural fibre-based composites with specific properties. Palm and pineapple leaf fibres were chosen in association with polypropylene (PP). The first step was to investigate the effect of these natural fibres as reinforcement for PP. The evolution of chemical structure and crystallinity was proposed with infrared spectroscopy measurements and differential scanning calorimetry thermograms, respectively. The assessments of mechanical properties with tensile tests and melt viscoelastic behaviour were also investigated. The study enabled to distinguish the influence of fibre content. The second step in our work was to assess the composite durability after ultraviolet exposure or thermal ageing. The oxidation level was calculated. The long-term evolution of thermal and mechanical properties was also proposed. As a result, the PP/pineapple leaf composite revealed a promising biocomposite.

scholarly journals Simultaneous Enhancement of Strength and Toughness of PLA Induced by Miscibility Variation with PVA

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1178 ◽  
Author(s):  
Yanping Liu ◽  
Hanghang Wei ◽  
Zhen Wang ◽  
Qian Li ◽  
Nan Tian
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Fracture Strain ◽  
Electrospun Fiber ◽  
Structural Evolution ◽  
Amorphous Structure ◽  
Poly Lactic Acid ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
Strength And Toughness

The mechanical properties of poly (lactic acid) (PLA) nanofibers with 0%, 5%, 10%, and 20% (w/w) poly (vinyl alcohol) (PVA) were investigated at the macro- and microscale. The macro-mechanical properties for the fiber membrane revealed that both the modulus and fracture strain could be improved by 100% and 70%, respectively, with a PVA content of 5%. The variation in modulus and fracture strain versus the diameter of a single electrospun fiber presented two opposite trends, while simultaneous enhancement was observed when the content of PVA was 5% and 10%. With a diameter of 1 μm, the strength and toughness of the L95V5 and L90V10 fibers were enhanced to over 3 and 2 times that of pure PLA, respectively. The structural evolution of electrospun nanofiber was analyzed by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). Although PLA and PVA were still miscible in the concentration range used, the latter could crystallize independently after electrospinning. According to the crystallization behavior of the nanofibers, a double network formed by PLA and PVA—one microcrystal/ordered structure and one amorphous structure—is proposed to contribute to the simultaneous enhancement of strength and toughness, which provides a promising method for preparing biodegradable material with high performance.

scholarly journals A method for pet mechanical properties enhancement

2019 ◽  
Vol 10 (8) ◽  
pp. 1725
Author(s):  
Raffaella Aversa ◽  
Relly Victoria Virgil Petrescu ◽  
Antonio Apicella ◽  
Florian Ion Tiberiu Petrescu
Keyword(s):  
Mechanical Properties ◽  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Molecular Structures ◽  
Reactive Blending ◽  
Scanning Calorimetry ◽  
Shear Transfer ◽  
Crystalline Polymers ◽  
Reactive Compatibilizer

A method for PET mechanical properties enhancement by reactive blending with HBA/HNA Liquid Crystalline Polymers for in situ highly fibrillar composites preparation is presented. LCP/PET blends were reactively extruded in presence of Pyromellitic Di-Anhydride (PMDA) and then characterized by Differential Scanning Calorimetry, Thermally Stimulated Currents and tensile mechanical properties. Moderate amounts of LCP in the PET (0.5 and 5%) and small amounts of thermo-active and reactive compatibilizer in the blend (0.3%) were found to significantly improve LCP melt dispersion, melts shear transfer and LCP fibril formation and adhesion. An unexpected improvement was probably due to the presence of two distinct phases’ supra-molecular structures involving PET-LCP and PMDA.

Phase Stability and Mechanical Properties of Ti(Ni, Ru) Alloys

2002 ◽  
Vol 753 ◽  
Author(s):  
Masahiro Tsuji ◽  
Hideki Hosoda ◽  
Kenji Wakashima ◽  
Yoko Yamabe-Mitarai
Keyword(s):  
Mechanical Properties ◽  
Phase Transformation ◽  
Phase Stability ◽  
Hot Forging ◽  
Tensile Tests ◽  
Lattice Parameter ◽  
Solid Solution Hardening ◽  
Scanning Calorimetry ◽  
Arc Melting ◽  
Transmission Electron

ABSTRACTEffects of ruthenium (Ru) substitution on constituent phases, phase transformation temperatures and mechanical properties were investigated for Ti-Ni shape memory alloys. Ti50Ni50-XRuX alloys with Ru contents (X) from 0mol% (binary TiNi) to 50mol% (binary TiRu) were systematically prepared by Ar arc-melting followed by hot-forging at temperatures from 1173K to 1673K depending on chemical composition. Phase stability was assessed by DSC (differential scanning calorimetry), XRD (X-ray diffractometry) and TEM (transmission electron microscopy). Mechanical properties were investigated using hardness and tensile tests at room temperature. With increasing Ru content, it was found that the lattice parameter of B2 phase increases, the martensitic transformation temperature slightly decreases, and the melting temperature increases monotonously. Besides, R-phase appears for Ti-Ni alloys containing 3mol% and 20mol%Ru but no diffusionless phase transformation is seen in Ti-Ni alloy containing 5mol%Ru. Vickers hardness shows the maximum at an intermediate composition (HV1030 at 30mol%Ru); this suggests that large solid solution hardening is caused by Ru substitution for the Ni-sites in TiNi.

The Structure and Mechanical Properties of Plastically Consolidated Al-Ni Alloy

2016 ◽  
Vol 682 ◽  
pp. 245-251 ◽  
Author(s):  
Grzegorz Włoch ◽  
Tomasz Skrzekut ◽  
Jakub Sobota ◽  
Antoni Woźnicki ◽  
Justyna Cisoń
Keyword(s):  
Mechanical Properties ◽  
Vickers Hardness ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Intermetallic Phases ◽  
Scanning Calorimetry ◽  
Porosity Formation ◽  
X Ray ◽  
Ni Alloy ◽  
Thermal Stability Of

Mixed and preliminarily consolidated powders of aluminium and nickel (90 mass % Al and 10 mass % Ni) were hot extruded. As results the rod, 8 mm in diameter, was obtained. As-extruded material was subjected to the microstructural investigations using scanning electron microscopy (SEM/EDS) and X-ray analysis (XRD). The differential scanning calorimetry (DSC) and thermo-mechanical analysis (TMA) were also performed. The mechanical properties of as extruded material were determined by the tensile test and Vickers hardness measurements. In order to evaluate the thermal stability of PM alloy, samples were annealed at the temperature of 475 and 550 °C. After annealing Vickers hardness measurements and tensile tests were carried out. The plastic consolidation of powders during extrusion was found to be very effective, because no pores or voids were observed in the examined material. The detailed microstructural investigations and XRD analyses did not reveal the presence of the intermetallic phases in the as-extruded material. During annealing, the Al3Ni intermetallic compound was formed as the result of chemical reaction between the alloy components. The hardness of the alloy after annealing at the temperature of 475°C was found to be comparable to the hardness in as-extruded state. Annealing of the material at the temperature of 550°C results in hardness decreasing by about 50%, as the consequence of porosity formation and Al3Ni cracking.

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