scholarly journals Crystallization, Structure and Significantly Improved Mechanical Properties of PLA/PPC Blends Compatibilized with PLA-PPC Copolymers Produced by Reactions Initiated with TBT or TDI

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3245
Author(s):  
Lixin Song ◽  
Yongchao Li ◽  
Xiangyu Meng ◽  
Ting Wang ◽  
Ying Shi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Strength ◽  
Average Molecular Weight ◽  
Toluene Diisocyanate ◽  
Chain Extension ◽  
Poly Lactic Acid ◽  
Cooling Process ◽  
Material Degradation ◽  
Elongation At Break ◽  
Poly Propylene

Poly (lactic acid) (PLA)-Poly (propylene carbonate) (PPC) block copolymer compatibilizers are produced in incompatible 70wt%PLA/PPC blend by initiating transesterification with addition of 1% of tetra butyl titanate (TBT) or by chain extension with addition of 2% of 2,4-toluene diisocyanate (TDI). The above blends can have much better mechanical properties than the blend without TBT and TDI. The elongation at break is dramatically larger (114% with 2% of TDI and 60% with 1% of TBT) than the blend without TDI and TBT, with a slightly lower mechanical strength. A small fraction of the copolymer is likely formed in the PLA/PPC blend with addition of TBT, and a significant amount of the copolymer can be made with addition of TDI. The copolymer produced with TDI has PPC as a major content (~70 wt%) and forms a miscible interphase with its own Tg. The crystallinity of the blend with TDI is significantly lower than the blend without TDI, as the PLA blocks of the copolymer in the interphase is hardly to crystallize. The average molecular weight increases significantly with addition of TDI, likely compensating the lower mechanical strength due to lower crystallinity. Material degradation can occur with addition of TBT, but it is very limited with 1% of TBT. However, compared with the blends without TBT, the PLA crystallinity of the blend with 1%TBT increases sharply during the cooling process, which likely compensates the loss of mechanical strength due to the slightly material degradation. The added TDI does not have any significant impact on PLA lamellar packing, but the addition of TBT can make PLA lamellar packing much less ordered, presumably resulted from much smaller PPC domains formed in the blend due to better compatibility.

scholarly journals A novel kind of room temperature self-healing poly(urethane-urea) with robust mechanical strength based on aromatic disulfide

2021 ◽  
Vol 28 (4) ◽  
Author(s):  
Jin He ◽  
Fangfang Song ◽  
Xiong Li ◽  
Liyi Chen ◽  
Xingyu Gong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Strength ◽  
Room Temperature ◽  
Toluene Diisocyanate ◽  
Self Healing ◽  
Isophorone Diisocyanate ◽  
Elongation At Break ◽  
Strength Based ◽  
Hard Segments ◽  
Poly Propylene

AbstractAn innovative poly(urethane-urea) elastomer, which exhibited excellent stretchability, thermal stability and autonomous self-healing abilities, was synthesized from the commercially available poly(propylene glycol) (PPG), isophorone diisocyanate (IPDI), 2,4 / 2,6-toluene diisocyanate (80: 20, w / w) (TDI-80) and bis (2-aminophenyl) disulfide (DSDA). This aromatic disulfide containing poly(urethane-urea) (ss-PUs) achieved both rapid room temperature self-healing abilities and robust mechanical strength (the ultimate tensile strength was up to 4.20 ± 0.10 MPa and elongation at break was up to 954 ± 35.6%), through facile metathesis of the aromatic disulfides which embedded in hard segments. After the ss-PUs was cut into two-halves and reconnected, the mechanical properties could recover to ~ 90% of those of the original samples within 12 h at room temperature without extra self-healing agents or any change of environmental conditions.

scholarly journals Sericin cocoon bio-compatibilizer for reactive blending of thermoplastic cassava starch

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Thanongsak Chaiyaso ◽  
Pornchai Rachtanapun ◽  
Nanthicha Thajai ◽  
Krittameth Kiattipornpithak ◽  
Pensak Jantrawut ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Maleic Anhydride ◽  
Crystal Size ◽  
Thermoplastic Starch ◽  
Cassava Starch ◽  
Chain Extension ◽  
Amino Groups ◽  
Reactive Blending ◽  
Elongation At Break ◽  
Small Crystal Size

AbstractCassava starch was blended with glycerol to prepare thermoplastic starch (TPS). Thermoplastic starch was premixed with sericin (TPSS) by solution mixing and then melt-blended with polyethylene grafted maleic anhydride (PEMAH). The effect of sericin on the mechanical properties, morphology, thermal properties, rheology, and reaction mechanism was investigated. The tensile strength and elongation at break of the TPSS10/PEMAH blend were improved to 12.2 MPa and 100.4%, respectively. The TPS/PEMAH morphology presented polyethylene grafted maleic anhydride particles (2 μm) dispersed in the thermoplastic starch matrix, which decreased in size to approximately 200 nm when 5% sericin was used. The melting temperature of polyethylene grafted maleic anhydride (121 °C) decreased to 111 °C because of the small crystal size of the polyethylene grafted maleic anhydride phase. The viscosity of TPS/PEMAH increased with increasing sericin content because of the chain extension. Fourier-transform infrared spectroscopy confirmed the reaction between the amino groups of sericin and the maleic anhydride groups of polyethylene grafted maleic anhydride. This reaction reduced the interfacial tension between thermoplastic starch and polyethylene grafted maleic anhydride, which improved the compatibility, mechanical properties, and morphology of the blend.

Effects of walnut shell powders on the morphology and the thermal and mechanical properties of poly(lactic acid)

2019 ◽  
Vol 33 (10) ◽  
pp. 1383-1395
Author(s):  
Hongjuan Zheng ◽  
Zhengqian Sun ◽  
Hongjuan Zhang
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Property Testing ◽  
Walnut Shell ◽  
Poly Lactic Acid ◽  
Thermal And Mechanical Properties ◽  
Scanning Calorimetry ◽  
Elongation At Break ◽  
Heat Distortion Temperature ◽  
Testing Techniques

Poly(lactic acid) (PLA) has good environmental compatibility, however, its high brittleness, slow rate of crystallization, and low heat distortion temperature restrict its widespread use. To overcome these limitations, in this study, PLA was mixed with walnut shell (WS) powders. The effects of WS powders on the morphology and the thermal and mechanical properties of PLA were investigated. The products were characterized by differential scanning calorimetry (DSC), infrared (IR) spectroscopy, polarizing optical microscopy (POM), and various mechanical property testing techniques. The results showed that WS powders had a significant effect on the morphology and the thermal and mechanical properties of PLA. The tensile strength, impact strength, and elongation at break of the PLA/WS composites first increased and then decreased with the increasing addition of WS powders. When the addition of WS powders was about 0.5 wt%, they reached maximum values of 51.2 MPa, 23.3 MPa, and 19.0%, respectively. Compared with neat PLA, the spherulite grain size of the composites could be reduced and many irregular polygons were formed during crystallization. The melting, cold crystallization, and glass-transition temperatures of the composites were lower than those of neat PLA.

scholarly journals A study on the mechanical, thermal properties and crystallization behavior of poly(lactic acid)/thermoplastic poly(propylene carbonate) polyurethane blends

RSC Advances ◽  
2017 ◽  
Vol 7 (73) ◽  
pp. 46183-46194 ◽  
Author(s):  
Jia Yang ◽  
Hongwei Pan ◽  
Xin Li ◽  
Shulin Sun ◽  
Huiliang Zhang ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Thermal Properties ◽  
Impact Strength ◽  
Propylene Carbonate ◽  
Crystallization Behavior ◽  
Raw Materials ◽  
Poly Lactic Acid ◽  
Elongation At Break ◽  
Poly Propylene ◽  
The Impact

PPCU was prepared by using PPC and polyols as the raw materials and diphenyl-methane-diisocyanate (MDI) as the extender chain. The impact strength and elongation at break of PLA were remarkably enhanced by blending with PPCU.

Mechanical and Morphological Behavior of Blends Obtained from Biopolymers (PLA/PLC)

2014 ◽  
Vol 775-776 ◽  
pp. 24-28
Author(s):  
Taciana Regina de Gouveia Silva ◽  
Bartira Brandão da Cunha ◽  
Pankaj Agrawal ◽  
Edcleide Maria Araújo ◽  
Tomás Jefférson Alves de Mélo
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Lactic Acid ◽  
Elastic Modulus ◽  
Impact Strength ◽  
Polymer Blends ◽  
Poly Lactic Acid ◽  
Elongation At Break ◽  
Morphology Analysis ◽  
Morphological Behavior

In this work, the effect of the PCL content and E-GMA compatibilizer on the mechanical properties and morphology of poly (lactic acid) - PLA/ poly (ε-caprolactone)-PCL blends was investigated. The results of the mechanical properties showed that there was a reduction in the elastic modulus and tensile strength when PCL was added to PLA. The decrease in the modulus was more pronounced when the PCL content was increased from 10 to 20% (wt). The PLA/PCL/E-GMA blend showed the lower modulus and tensile strength. This blend also presented the higher elongation at break and impact strength. The morphology analysis by SEM showed that the PLA/PCL blends where characterized by lack of adhesion between the PLA and PCL phases. The presence of E-GMA in the PLA/PCL/E-GMA blend improved the adhesion between the PLA and PCL phases.Keywords: poly (latic acid); poly (ε-caprolactone); polymer blends; compatibilizer

scholarly journals Sericin cocoon bio-compatibilizer for reactive blending of thermoplastic cassava starch

2021 ◽  
Author(s):  
Thanongsak Chaiyaso ◽  
Pornchai Rachtanapun ◽  
Nanthicha Thajai ◽  
Krittameth kiattipronpithak ◽  
Pensak Jantrawut ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Maleic Anhydride ◽  
Crystal Size ◽  
Thermoplastic Starch ◽  
Cassava Starch ◽  
Chain Extension ◽  
Amino Groups ◽  
Reactive Blending ◽  
Elongation At Break ◽  
Small Crystal Size

Abstract Cassava starch was blended with glycerol to prepare thermoplastic starch (TPS). TPS was premixed with sericin (TPSS) by solution mixing and then melt-blended with polyethylene grafted maleic anhydride (PEMAH). The effect of sericin on the mechanical properties, morphology, thermal properties, rheology, and reaction mechanism was investigated. The tensile strength and elongation at break of the TPSS10/PEMAH blend were improved to 12.2 MPa and 100.4%, respectively. The TPS/PEMAH morphology presented PEMAH particles (2 µm) dispersed in the TPS matrix, which decreased in size to approximately 200 nm when 5% sericin was used. The melting temperature of PEMAH (121°C) decreased to 111°C because of the small crystal size of the PEMAH phase. The viscosity of TPS/PEMAH increased with increasing sericin content because of the chain extension. Fourier-transform infrared spectroscopy (FTIR) confirmed the reaction between the amino groups of sericin and the maleic anhydride groups of PEMAH. This reaction reduced the interfacial tension between TPS and PEMAH, which improved the compatibility, mechanical properties, and morphology of the blend.

Study on Mechanical Properties of Polyurethane Elastomers for Drum Scraper

2011 ◽  
Vol 284-286 ◽  
pp. 2384-2387
Author(s):  
Jin Cui Zhang ◽  
Xi Jun Liu ◽  
Tie Ning Ma
Keyword(s):  
Mechanical Properties ◽  
Chain Extender ◽  
Glycol Ether ◽  
Toluene Diisocyanate ◽  
Chain Extension ◽  
Molar Ratio ◽  
Casting Method ◽  
Polyurethane Elastomers ◽  
Application Requirements

Polyurethane elastomers (PUE) were prepared by casting method using the prepolymer and the chain extender. In here, the prepolymer synthesized by using poly(tetramethylene glycol ether) (PTMG) and toluene diisocyanate (TDI), the chain extender was a mixture of 3,5-dimetylthio toluene diamine (E-300) and triethanolamine. The effects of the NCO concentration in prepolymer, the molar ratio of E-300/triethanolamine, and the chain extension coefficient of NCO/NH2 on the mechanical properties of the prepared PUE were studied. The results showed that the prepared PUE possesses excellent mechanical properties which can meet the drum scraper’s application requirements when the NCO concentration in prepolymer was 5.06% and the molar ratio of composite chain extender was 0.92/0.08.

scholarly journals The Preparation and Properties of Nanocomposite from Bio-Based Polyurethane and Graphene Oxide for Gas Separation

Nanomaterials ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 15 ◽  
Author(s):  
Yongsheng Zhang ◽  
Jun Ma ◽  
Yao Bai ◽  
Youwei Wen ◽  
Na Zhao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Gas Separation ◽  
Hybrid Film ◽  
Gas Permeability ◽  
Chain Extension ◽  
Gravimetric Analysis ◽  
Elongation At Break ◽  
Tung Oil ◽  
Thermal Stability Of

Petroleum depletion and climate change have inspired research on bio-based polymers and CO2 capture. Tung-oil-based polyols were applied to partially replace polyether-type polyols from petroleum for sustainable polyurethane. Tung-oil-based polyurethane (TBPU), was prepared via a two-step polycondensation, that is, bulk prepolymerization and chain extension reaction. The graphene oxide (GO) was prepared via Hummer’s method. Then, TBPU was composited with the GO at different ratios to form a TBPU/GO hybrid film. The GO/TBPU films were characterized by fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), thermal gravimetric analysis (TGA) and scanning electron microscope (SEM), followed by the measurement of mechanical properties and gas permeability. The results showed that the addition of tung-oil-based polyols enhanced the glass transition temperature and thermal stability of TBPU. The mechanical properties of the hybrid film were significantly improved, and the tensile strength and elongation at break were twice as high as those of the bulk TBPU film. When the GO content was higher than 2.0%, a brittle fracture appeared in the cross section of hybrid film. The increase of GO content in hybrid films improved the selectivity of CO2/N2 separation. When the GO content was higher than 0.35%, the resulting GO agglomeration constrained the gas separation and permeation properties.

Sign in / Sign up

Export Citation Format

Share Document