scholarly journals Comparison of Precipitated Calcium Carbonate/Polylactic Acid and Halloysite/Polylactic Acid Nanocomposites

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Xuetao Shi ◽  
Guangcheng Zhang ◽  
Cristina Siligardi ◽  
Guido Ori ◽  
Andrea Lazzeri
Keyword(s):  
Glass Transition ◽  
Calcium Carbonate ◽  
Polylactic Acid ◽  
Halloysite Nanotubes ◽  
Mechanical Analysis ◽  
Precipitated Calcium Carbonate ◽  
Dynamical Mechanical Analysis ◽  
Elongation At Break ◽  
Ultimate Deformation ◽  
Tensile Performance

PLA nanocomposites with stearate coated precipitated calcium carbonate (PCC) and halloysite natural nanotubes (HNT) were prepared by melt extrusion. The crystallization behavior, mechanical properties, thermal dynamical mechanical analysis (DMTA), and the morphology of the PCC/PLA, HNT/PLA, and HNT/PCC/PLA composites were discussed. Compared to halloysite nanotubes, PCC nanoparticles showed a better nucleating effect, which decreased both the glass transition and cold crystallization temperatures. The tensile performance of PLA composites showed that the addition of inorganic nanofillers increased Young’s modulus but decreased tensile strength. More interestingly, PLA composites with PCC particles exhibited an effectively increased elongation at break with respect to pure PLA, while HNT/PLA showed a decreased ultimate deformation of composites. DMTA results indicated that PLA composites had a similar storage modulus at temperatures below the glass transition and the addition of nanofillers into PLA causedTgto shift to lower temperatures by about 3°C. The morphological analysis of fractures surface of PLA nanocomposites showed good dispersion of nanofillers, formation of microvoids, and larger plastic deformation of the PLA matrix when the PCC particles were added, while a strong aggregation was noticed in composites with HNT nanofillers, which has been attributed to a nonoptimal surface coating.

Poly(lactic acid) phase transitions in the presence of nano calcium carbonate: Opposing effect of nanofiller on static and dynamic measurements

2018 ◽  
Vol 32 (3) ◽  
pp. 312-327 ◽  
Author(s):  
Omid Yousefzade ◽  
Javad Jeddi ◽  
Elham Vazirinasab ◽  
Hamid Garmabi
Keyword(s):  
Lactic Acid ◽  
Glass Transition ◽  
Calcium Carbonate ◽  
Mechanical Analysis ◽  
Polymer Chains ◽  
Poly Lactic Acid ◽  
Modulated Dsc ◽  
Scanning Calorimetry ◽  
Chain Mobility ◽  
Dispersion State

The effect of stearic acid-coated nano calcium carbonate (NCC) on transitions and chain mobility of poly(lactic acid) (PLA) was investigated. Dispersion state of NCC in polymeric matrix was explored using scanning electron microscopy and surface tension component measurements. Trends of PLA transitional phenomena were investigated using the results of dynamical mechanical analysis (DMA) and differential scanning calorimetry (DSC) in the nanocomposite systems based on PLA and NCC. In addition, two types of crystal structures and decreasing the glass transition temperature were distinguished using temperature-modulated DSC (TMDSC). Higher melting points of polymer crystals were found in TMDSC experiments due to low and dynamic heating rate compared to the conventional DSC. Dynamics of polymer chains, affected by NCC, were quantified using cooperativity length, ξ α, and the number of relaxing structural units, Nα, in the glass transition region. NCC particles hindered the cooperative motion of polymer chains at glass transitions and crystallization in TMDSC measurements, whereas the DMA results indicated that NCC particles may act as lubricant and simplified chain mobility.

scholarly journals Enhanced Flexibility of Biodegradable Polylactic Acid/Starch Blends Using Epoxidized Palm Oil as Plasticizer

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 977 ◽  
Author(s):  
Raina Awale ◽  
Fathilah Ali ◽  
Azlin Azmi ◽  
Noor Puad ◽  
Hazleen Anuar ◽  
...  
Keyword(s):  
Polylactic Acid ◽  
Palm Oil ◽  
Mechanical Analysis ◽  
Elongation At Break ◽  
Soil Burial ◽  
Chain Mobility ◽  
Epoxidized Palm Oil ◽  
Aliphatic Ester ◽  
Starch Blends ◽  
Solution Casting Method

The brittleness of polylactic acid (PLA) has always limited its usage, although it has good mechanical strength. In this study, flexibility of PLA/starch (PSt) blend was enhanced using epoxidized palm oil (EPO) as the green plasticizer. The PLA/starch/EPO (PSE) blends were prepared while using the solution casting method by fixing the content of starch and varying ratio of EPO. The thermal properties, such as glass transition temperature (Tg), melting temperature (Tm), and crystallization temperature (Tcc) were decreased by increasing the amount of EPO into PSt, indicating that EPO increases the chain mobility. Thermogravimetric analysis (TGA) showed that thermal degradation resistance of PSE was higher when compared to PSt. The mechanical testing revealed that EPO at all contents improved the mechanical properties, such as increment of the elongation-at-break and impact strength. Whereas, dynamic mechanical analysis showed that the addition of filler into PLA decreased the storage modulus of PLA. The carbonyl group of the aliphatic ester remained the same in the PSE blends. The morphological study verified the ductility of PSE blends surface when compared to the brittle surface of PSt. As for the soil burial tests, EPO accelerated the degradation of blends. From these results, it can be concluded that EPO improved the flexibility of PLA blends.

Tailoring Polylactic Acid Properties for Packaging Applications: Effects of Co‐Addition of Halloysite Nanotubes and Selected Plasticizers

2020 ◽  
Vol 1002 ◽  
pp. 47-56
Author(s):  
Abdulkader M. Alakrach ◽  
Nik Noriman Zulkepli ◽  
Awad A. Al-Rashdi ◽  
Sam Sung Ting ◽  
Rosniza Hamzah ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polylactic Acid ◽  
Thermal Analyses ◽  
Weight Ratio ◽  
Tensile Modulus ◽  
Halloysite Nanotubes ◽  
Low Molecular Weight ◽  
Elongation At Break ◽  
Co Addition

Polylactic acid (PLA) has recently given a huge attention because of its mechanical properties and good physical like good biodegradability and processability, high tensile modulus and strength. In the current research, the researchers utilized sesame oil (SO) and low molecular weight polyethylene glycol (PEG) as hydrophobic and hydrophilic plasticizers, towards improvise the ductility and toughness of PLA. The researchers synthesized nanocomposites by solution casting of the neat PLA/HNTs and PLA blends with weight ratio of (0,10, 20 and 30 wt%) for PEG and (0, 5 and 10 wt%) for SO. The influence of both plasticizers on chemical, thermal and mechanical properties of the nanocomposites were investigated. Characterization of the systems was achieved by mechanical testing and thermogravimetric analysis (TGA), field emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FTIR). The FTIR analyses confirmed the existing of hydrogen bonding between PLA and both PEG and SO. significant improvement was shown by the plasticized nanocomposites in elongation at break with the adding of PEG and SO, meanwhile, the plasticized films’ strength were decreased. For the thermal analyses, all the films exhibited lower thermal stability compared to PLA/HNTs film.

scholarly journals Ethylene-Octene Copolymers/Organoclay Nanocomposites: Preparation and Properties

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Alice Tesarikova ◽  
Dagmar Merinska ◽  
Jiri Kalous ◽  
Petr Svoboda
Keyword(s):  
Barrier Properties ◽  
Mechanical Analysis ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Uv Aging ◽  
Dynamical Mechanical Analysis ◽  
Elongation At Break ◽  
X Ray ◽  
Transmission Electron ◽  
Nucleation Agents

Two ethylene-octene copolymers with 17 and 45 wt.% of octene (EOC-17 and EOC-45) were compared in nanocomposites with Cloisite 93A. EOC-45 nanocomposites have a higher elongation at break. Dynamical mechanical analysis (DMA) showed a decrease oftan⁡δwith frequency for EOC-17 nanocomposites, but decrease is followed by an increase for EOC-45 nanocomposites; DMA showed also increased modulus for all nanocomposites compared to pure copolymers over a wide temperature range. Barrier properties were improved about 100% by addition of organoclay; they were better for EOC-17 nanocomposites due to higher crystallinity. X-ray diffraction (XRD) together with transmission electron microscopy (TEM) showed some intercalation for EOC-17 but much better dispersion for EOC-45 nanocomposites. Differential scanning calorimetry (DSC) showed increased crystallization temperatureTcfor EOC-17 nanocomposite (aggregates acted as nucleation agents) but decreaseTcfor EOC-45 nanocomposite together with greatly influenced melting peak. Accelerated UV aging showed smaller C=O peak for EOC-45 nanocomposites.

scholarly journals Effect of HNT on mechanical and thermal properties of poly(lactic acid)/polypropylene carbonate blends

Polimery ◽  
2021 ◽  
Vol 66 (9) ◽  
pp. 459-465
Author(s):  
Intan Najwa Humaira Mohamed Haneef ◽  
Yose Fachmi Buys ◽  
Norhashimah Mohd Shaffiar ◽  
Sharifah Imihezri Syed Shaharuddin ◽  
Abdul Malek Abdul Hamid ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Glass Transition ◽  
Thermal Properties ◽  
Halloysite Nanotubes ◽  
Poly Lactic Acid ◽  
Mechanical And Thermal Properties ◽  
Melt Mixing ◽  
Elongation At Break ◽  
Young’S Moduli ◽  
Dsc Thermograms

In this work, the influence of halloysite nanotubes (HNTs) on the mechanical and thermal properties of the poly(lactic acid)/polypropylene carbonate (PLA/PPC 70/30) blend was studied. The HNT was incorporated into the PLA/PPC blend by melt mixing. It was found that addition of 2-6 wt % HNT successfully improved the tensile and flexural strength as well as the flexural and Young’s  moduli of PLA/PPC blend, due to the reinforcing effect. Although the elongation at break decreases with increasing HNT content, its value is much higher than that of pure PLA. Moreover, the addition of HNT didnot affect the miscibility of PLA and PPC, since two glass transition temperatures were observed in the DSC thermograms. However, a higher content of HNT may improve the compatibility between PLA and PPC as evidenced by the lower difference between the glass transition temperature of PPC and PLA and reduced crystallinity resulting in higher tensile strength of nanocomposites.Keywords: PLA, PPC, HNT, mechanical properties, thermal properties.

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
Keyword(s):  
Mechanical Properties ◽  
Polylactic Acid ◽  
Mechanical Analysis ◽  
Melt Blending ◽  
Pseudoplastic Fluid ◽  
Obvious Effect ◽  
Elongation At Break ◽  
Thermodynamic Compatibility ◽  
The Poor ◽  
The Impact

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.

Dynamical mechanical analysis of glass-transition peaks in polymers and composites

1994 ◽  
Vol 211-212 ◽  
pp. 381-384 ◽  
Author(s):  
D.P. Almond ◽  
B. Harris ◽  
R.G. Hallett ◽  
O.G. Braddell
Keyword(s):  
Glass Transition ◽  
Mechanical Analysis ◽  
Dynamical Mechanical Analysis

A method for measuring the in-plane compressive strength and the compression behavior of coating layers

TAPPI Journal ◽  
2011 ◽  
Vol 10 (7) ◽  
pp. 29-34
Author(s):  
TEEMU PUHAKKA ◽  
ISKO KAJANTO ◽  
NINA PYKÄLÄINEN
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Calcium Carbonate ◽  
Coating Layer ◽  
Test Methods ◽  
Coating Films ◽  
Precipitated Calcium Carbonate ◽  
Coating Color ◽  
Mineral Coatings ◽  
Styrene Butadiene

Cracking at the fold is a quality defect sometimes observed in coated paper and board. Although tensile and compressive stresses occur during folding, test methods to measure the compressive strength of a coating have not been available. Our objective was to develop a method to measure the compressive strength of a coating layer and to investigate how different mineral coatings behave under compression. We used the short-span compressive strength test (SCT) to measure the in-plane compressive strength of a free coating layer. Unsupported free coating films were prepared for the measurements. Results indicate that the SCT method was suitable for measuring the in-plane compressive strength of a coating layer. Coating color formulations containing different kaolin and calcium carbonate minerals were used to study the effect of pigment particles’ shape on the compressive and tensile strengths of coatings. Latices having two different glass transition temperatures were used. Results showed that pigment particle shape influenced the strength of a coating layer. Platy clay gave better strength than spherical or needle-shaped carbonate pigments. Compressive and tensile strength decreased as a function of the amount of calcium carbonate in the coating color, particularly with precipitated calcium carbonate. We also assessed the influence of styrene-butadiene binder on the compressive strength of the coating layer, which increased with the binder level. The compressive strength of the coating layer was about three times the tensile strength.

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