Prediction of tensile modulus from calorimetric melting curves of polylactic acid with pronounced cold crystallization ability

Polylactic acid (PLA) is one of the most promising bio-based materials, but its inherent hydrophobicity limits its application. Although nanocellulose (NCC) is a desirable reinforcement for PLA, the poor interface compatibility between the two has been a challenge. In this work, hydroxyapatite (HAP) modified NCC was prepared, and the obtained NCC/HAP reinforcement was used to prepare PLA/NCC-HAP composites. Different ratios of NCC to HAP were studied to explore their effects on the mechanical and thermodynamic properties of the composites. When the ratio of NCC to HAP was 30/70, the tensile strength and tensile modulus of the composite film reached 45.6 MPa and 2.34 GPa, respectively. Thermogravimetric analysis results indicate that thermal stability of the composites was significantly improved compared with pure PLA, reaching 346.6 °C. The above revelations show that NCC/HAP significantly improved the interface compatibility with PLA matrix.

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The Effect of Sequence Structure of Polyisoprene on its Crystallization and Reinforcement

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.815.201 ◽

2013 ◽

Vol 815 ◽

pp. 201-204

Author(s):

Shu Guang Li ◽

Jin Mei Tan ◽

Jing Wei He ◽

Si Zhu Wu

Keyword(s):

Regular Sequence ◽

Cold Crystallization ◽

Sequence Structure ◽

Crystallization Ability ◽

Stress Induced Crystallization ◽

Induced Crystallization ◽

C Nmr

soprene can be polymerized into three types of isomeric units, cis-1, 4, trans-1, 4 and 3, 4-units. Dyad or triad sequences of these units were investigated by 13C-NMR, which the signals are assigned for the sequences as well as the special linkages, head-to-head and head-to-tail structures. The crystallization ability of polyisoprene was mainly dependent on these sequence structures and was studied in this paper, including cold crystallization and stress-induced crystallization. As a result, the samples with regular sequence structure had better crystallized ability which will be as the guidance for the polymerization.

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Injection Molded of Bio-Micro-Composites from Natural Fibers and Polylactic Acid

Wood Research Journal ◽

10.51850/wrj.2011.2.1.21-26 ◽

2017 ◽

Vol 2 (1) ◽

pp. 21-26

Author(s):

Subyakto Subyakto ◽

Euis Hermiati ◽

Nanang Masruchin ◽

Ismadi Ismadi ◽

Kurnia Wiji Prasetiyo ◽

...

Keyword(s):

Tensile Strength ◽

Flexural Strength ◽

Polylactic Acid ◽

Flexural Modulus ◽

Natural Fibers ◽

Tensile Modulus ◽

Optimum Composition ◽

Automotive Application ◽

Composition Ratio ◽

Sisal Fibers

Green composites were needed by automotive industries because they are environmentally friendly, recyclable, lightweight and strong. Natural fibers such as bamboo and sisal are potential source of these materials and can be used as substitutes of fiber glass which is hard to recycle and not renewable. In this experiment, bio-composites made from micro fibers of betung bamboo (Dendrocalamus asper) and sisal (Agave sisalana) mixed with a natural polymer of polylactic acid (PLA) were developed that may used for automotive application. Bamboo or sisal fibers were converted into pulp and processed using a disc refiner to produce microfibrillated cellulose (MFC) with fiber diameter around 10 µm. MFC was mixed with PLA and triacetin and dried. The mixture was processed in a mixer at temperature of 170ºC, speed of 60 rpm for 20 min. The compound mixture was removed and processed into pellets using a pelletizer at 170ºC. Pellets were processed using injection molding machine. The compositions of fibers/PLA were 10/90, 20/80, and 30/70. The mechanical properties were tested in accordance with ASTM standards. Result shown that optimum composition ratio of bamboo fibers/PLA was 20/80 which gave flexural strength of 62.30 MPa, flexural modulus of 3.89 GPa, tensile strength of 44.55 MPa, tensile modulus of 1.20 GPa, and hardness of 112.90 R. While the optimum composition ratio of sisal fibers/PLA was 30/70 which gave flexural strength of 67.83 MPa, flexural modulus of 4.43 GPa, tensile strength of 48.18 MPa, tensile modulus of 1.13 GPa, and hardness of 110.50 R.

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Valorization of Sugarcane Straw for the Development of Sustainable Biopolymer-Based Composites

Polymers ◽

10.3390/polym13193335 ◽

2021 ◽

Vol 13 (19) ◽

pp. 3335

Author(s):

Jorge R. Robledo-Ortíz ◽

Alan S. Martín del Campo ◽

Juan A. Blackaller ◽

Martín E. González-López ◽

Aida A. Pérez Fonseca

Keyword(s):

Tensile Strength ◽

Impact Strength ◽

Flexural Strength ◽

Polylactic Acid ◽

Industrial Waste ◽

Tensile Modulus ◽

Industrial Applications ◽

Added Value ◽

Sugarcane Straw ◽

Filler Reinforcement

Sugarcane straw (SCS) is a common agro-industrial waste that is usually incinerated or discarded in fields after harvesting, increasing the importance of developing added-value applications for this residue. In this study, sustainable biocomposites were produced, and the effect of sugarcane straw as a filler/reinforcement of commercial biopolymers was evaluated. Biocomposites were prepared using polylactic acid (PLA), polyhydroxybutyrate (PHB), polyhydroxybutyrate-co-hydroxyvalerate (PHBV), or green polyethylene (Green-PE) with different fiber contents (20, 30, and 40 wt.%). Dry-blending followed by compression molding was used for the biocomposites preparation. The results showed that PLA, PHB, and PHBV biocomposites retained the same impact strength as the neat matrices, even with 40 wt.% of sugarcane straw. The flexural and tensile modulus of PLA, PHB, and PHBV biocomposites increased with 20% of SCS, whereas, in Green-PE biocomposites, these properties increased at all fiber contents. Since any compatibilizer was used, both the flexural and tensile strength decreased with the addition of SCS. However, even with the highest content of SCS, the tensile and flexural strength values were around 20 MPa, making these materials competitive for specific industrial applications.

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ISOTHERMAL COLD CRYSTALLIZATION BEHAVIOR OF AMORPHOUS POLYLACTIC ACID PREPARED BY RAPID COMPRESSION

Acta Polymerica Sinica ◽

10.3724/sp.j.1105.2013.12377 ◽

2013 ◽

Vol 013 (8) ◽

pp. 1085-1091 ◽

Cited By ~ 2

Author(s):

Zhang Rui-jing ◽

Shao Chun-guang ◽

Li Qian ◽

Wang Ming-you ◽

Zhang Dou-dou ◽

...

Keyword(s):

Polylactic Acid ◽

Crystallization Behavior ◽

Cold Crystallization ◽

Rapid Compression

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In Situ Synthesis and Mechanical Properties of Polylactic Acid/Hydroxyapatite Functionalized Graphene Nanocomposite

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.735.230 ◽

2017 ◽

Vol 735 ◽

pp. 230-234

Author(s):

Aekkapan Sriboonrung ◽

Siree Tangbunsuk ◽

Chomdao Sinthuvanich ◽

Wirunya Keawwattana

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Polylactic Acid ◽

Tensile Modulus ◽

Precipitation Method ◽

Functionalized Graphene ◽

X Ray Diffraction ◽

Elongation At Break ◽

Graphene Nanocomposite

The hydroxyapatite functionalized graphene (HAp-GnP) was prepared by precipitation method. It was characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Polylactic acid (PLA)/HAp-GnP and PLA/HAp-GnP composites were prepared in film by solution casting. The amount of HAp-GnP and HAp/GnP filled in PLA was fixed at 5% (by weight). The influence of HAp-GnP in the mechanical properties including tensile strength (TS), tensile modulus (E) and elongation at break (EB) of composites was investigated. It was found that tensile strength (TS) and tensile modulus (E) of the PLA/HAp-GnP composite were higher than those of PLA/HAp/GnP composite as a result of HAp making the interfacing with graphene leading to the greater distribution of HAp-GnP in PLA matrix. The PLA/HAp-GnP composite is applicable to be applied as bone substitute in the future.

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Effect of short basalt fibers on durability, mechanical properties, and thermal properties of polylactic acid composites

Polymers from Renewable Resources ◽

10.1177/2041247919863631 ◽

2019 ◽

Vol 10 (1-3) ◽

pp. 45-59

Author(s):

Lu Han ◽

Fangwu Ma ◽

Shixian Chen ◽

Yongfeng Pu

Keyword(s):

Mechanical Properties ◽

Polylactic Acid ◽

Basalt Fiber ◽

Tensile Modulus ◽

Accelerated Aging ◽

Mechanical Analysis ◽

Basalt Fibers ◽

Scanning Calorimetry ◽

Accelerated Aging Test ◽

Aging Test

The effect of basalt fiber (BF) content on the properties of BF-reinforced polylactic acid (PLA) composites was investigated. Composites with 10, 20, 30, 40, 50, and 60 wt% BF were fabricated. The results revealed that (1) the mechanical properties improved with increasing BF content. The maximum tensile strength and modulus of the composites (i.e. 140 and 5050 MPa, respectively) occurred at a BF content of 50%. The maximum flexural strength, that is, 159.5 MPa was two times larger than that of the pure PLA and was obtained at a BF content of 40%. However, the mechanical properties deteriorated at BF contents >50%. (2) BF can stop storage modulus loss and are effective in improving the crystallinity, as revealed by dynamic mechanical analysis and differential scanning calorimetry measurements. The crystallinity improved from 34.6% to 54.6% with BF addition. (3) After the accelerated aging test, pure PLA was too weak for testing. However, high values of the tensile modulus (i.e. 60% that of the nonaged samples) were maintained by the BF-reinforced PLA. This resulted possibly from the high crystallinity of the PLA composites. Therefore, suitable amounts of BF as reinforcements can yield improvements in the performance of PLA composites.

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Cellulose nanofibrils and nano-scaled titanium dioxide-reinforced biopolymer nanocomposites: Selecting the best nanocomposites with multicriteria decision-making methods

Journal of Composite Materials ◽

10.1177/0021998319870842 ◽

2019 ◽

Vol 54 (7) ◽

pp. 923-935

Author(s):

Havva Gumus ◽

Deniz Aydemir ◽

Ertugrul Altuntas ◽

Rıfat Kurt ◽

Erol Imren

Keyword(s):

Decision Making ◽

Titanium Dioxide ◽

Polylactic Acid ◽

Cellulose Nanofibrils ◽

Tensile Modulus ◽

Multicriteria Decision Making ◽

Accelerated Weathering ◽

Electron Microscopic ◽

Multicriteria Decision ◽

Decay Test

The aim of the paper is to determine the effects of nano fillers such as cellulose nanofibrils and nano-scaled titanium dioxide on some properties of polyhydroxybutyrate and polylactic acid biopolymers; it also determined the selection of biopolymer nanocomposites with the optimum properties by using multicriteria decision-making methods such as multi-attribute utility theory, simple additive weighting, and weighted aggregated sum product assessment. Test results showed that the mechanical properties of the biopolymer nanocomposites generally increased with the addition of the cellulose nanofibrils and nano-scaled titanium dioxide. However, the addition of nano-scaled titanium dioxide decreased the tensile modulus. The addition of the cellulose nanofibrils had a higher effect on the tensile and flexure modulus of elasticity than the addition of the nano-scaled titanium dioxide. Thermal properties were generally found to improve with the addition of the cellulose nanofibrils and nano-scaled titanium dioxide. Melting temperature (Tm) generally decreased with the addition of the nano fillers. The scanning electron microscopic images showed that the nano fillers were dispersed as white dots in the biopolymer matrix. After accelerated weathering and decay test, outdoor performance of the biopolymer nanocomposites was found to be improved with the addition of the nano fillers. Multicriteria decision-making methods were conducted to determine the biopolymer nanocomposites having the optimum properties, and all the methods showed that the best biopolymer nanocomposites was polylactic acid with 1% cellulose nanofibrils.

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

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1002.47 ◽

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.

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