scholarly journals Minor Special Issue of Polymeric Materials. Stretching Process of Poly-l-lactic Acid Films and their Structure and Properties.

1994 ◽  
Vol 43 (495) ◽  
pp. 1520-1524 ◽  
Author(s):  
Kiyoichi MATSUMOTO ◽  
Makoto OGAITO ◽  
Masakazu KOBAYASHI ◽  
Eiichi OZEKI ◽  
Shu TAHARA
Keyword(s):  
Lactic Acid ◽  
Polymeric Materials ◽  
Structure And Properties ◽  
Special Issue ◽  
Stretching Process

scholarly journals In Vitro and In Vivo Biosafety Analysis of Resorbable Polyglycolic Acid-Polylactic Acid Block Copolymer Composites for Spinal Fixation

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 29
Author(s):  
Seung Kyun Yoon ◽  
Jin Ho Yang ◽  
Hyun Tae Lim ◽  
Young-Wook Chang ◽  
Muhammad Ayyoob ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Animal Experiments ◽  
Polymeric Materials ◽  
Polyglycolic Acid ◽  
Poly Lactic Acid ◽  
Skin Sensitization ◽  
Spinal Fixation ◽  
In Vivo Degradation

Herein, spinal fixation implants were constructed using degradable polymeric materials such as PGA–PLA block copolymers (poly(glycolic acid-b-lactic acid)). These materials were reinforced by blending with HA-g-PLA (hydroxyapatite-graft-poly lactic acid) and PGA fiber before being tested to confirm its biocompatibility via in vitro (MTT assay) and in vivo animal experiments (i.e., skin sensitization, intradermal intracutaneous reaction, and in vivo degradation tests). Every specimen exhibited suitable biocompatibility and biodegradability for use as resorbable spinal fixation materials.

Investigation of changes in physical and mechanical parameters of biodegradable polymer films during composting

2021 ◽  
pp. 40-43
Author(s):  
Дмитрий Михайлович Мяленко
Keyword(s):  
Lactic Acid ◽  
Environmental Protection ◽  
Biodegradable Polymer ◽  
Polymeric Materials ◽  
Mechanical Parameters ◽  
Ecological Situation ◽  
Plant Materials ◽  
Foreign Countries ◽  
Hydrolysis Of ◽  
Aliphatic Biopolymer

Вопросы защиты окружающей среды и улучшения экологической обстановки приобретают глобальный характер. Количество производимых в России и зарубежных странах синтетических полимерных материалов постоянно увеличивается, что заставляет задуматься о подходах к разработке современных биоразлагаемых полимерных материалов из полностью возобновляемого растительного сырья. Один из таких материалов - это линейный алифатический биополимер, полученный путем гидролиза молочной кислоты: полилактид (PLA). В данной статье представлены результаты исследований способности к биоразложению полимерных материалов на основе PLA при их компостировании в течение 3 мес. The issues of environmental protection and improvement of the ecological situation are becoming global in nature. The number of synthetic polymeric materials produced from Russia and foreign countries is constantly increasing, which makes us think about approaches to the development of modern biodegradable polymeric materials from completely renewable plant materials. One such material is a linear aliphatic biopolymer made by hydrolysis of lactic acid: polylactide (PLA). This article presents the results of studies on the biodegradability of PLA-based polymeric materials when composted for 3 months.

scholarly journals Special Issue of the Manufacturing Engineering Society (MES)

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2149 ◽  
Author(s):  
Eva Rubio ◽  
Ana Camacho
Keyword(s):  
Molecular Level ◽  
Materials Processing ◽  
Manufacturing Processes ◽  
Structure And Properties ◽  
Special Issue ◽  
Or Management ◽  
Engineering Society ◽  
Manufacturing Engineering

Research in the field of materials is very broad, ranging from studies on the structure and properties at the atomic or molecular level to the most complex or sophisticated applications that can be done with them, as well as studies about other aspects related to their processing, use or management. The Special Issue of the Manufacturing Engineering Society (MES), published in the Section “Manufacturing Processes and Systems” of the journal Materials, focuses, mainly, on the applications and key processing aspects of materials, collecting a set of 48 original papers focused on the field of manufacturing engineering and materials processing.

scholarly journals Synthesis of polylactic acid-diol (PLA-diol) from lactic acid and 1,4-butanediol

2016 ◽  
Vol 19 (4) ◽  
pp. 58-65
Author(s):  
Ha Thi Thai La
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Polyethylene Glycol ◽  
1H Nmr ◽  
Biodegradable Polymer ◽  
Average Molecular Weight ◽  
Chain Extension ◽  
Structure And Properties ◽  
Chain Reaction ◽  
A Chain

In this research, the PLA-diol were synthesized from lactic acid (LA) and 1.4 butanediols (BD) with a tin octoate Sn(Oct)2 catalyst at a temperature of 180 °C and the pressure 5 mmHg. The structure and properties of PLA-diol are analyzed by the following methods: GPC, 1H-NMR and DSC. As a result, with the change in the content of Sn (Oct)2 from 0.1 to 1.0%, the molecular weight Mn of PLA - diol increased gradually from 4.119,2 to 7.359,6 g / mol . In addition, the BD content increased from 2.0% to 5.0%, the average molecular weight of the product decreased gradually from 7.536,9 g / mol to 4.735 g / mol, respectively. This change will affect the ability to use PLA-diol in the next denaturation research to apply in the field of biodegradable polymer such as copolymer with polyurethane, copolymer with polyethylene glycol diacid, or chain extension with other polymer in a chain reaction,...

Location Depending Textures of the Human Dental Enamel

2010 ◽  
Vol 160 ◽  
pp. 281-286 ◽  
Author(s):  
Lars Raue ◽  
Helmut Klein
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Dental Enamel ◽  
Polymeric Materials ◽  
Incisor Tooth ◽  
Worst Case ◽  
Dental Fillings ◽  
Anisotropic Mechanical Properties ◽  
Different Types ◽  
Materials Used

Dental enamel is the most highly mineralised and hardest biological tissue in human body [1]. Dental enamel is made of hydroxylapatite (HAP) - Ca5(PO4)3(OH), which is hexagonal (6/m). The lattice parameters are a = b = 0.9418 nm und c = 0.6875 nm [1]. Although HAP is a very hard mineral, it can be dissolved easily in a process which is known as enamel demineralization by lactic acid produced by bacteria. Also the direct consumption of acid (e.g. citric, lactic or phosphoric acid in soft drinks) can harm the dental enamel in a similar way. These processes can damage the dental enamel. It will be dissolved completely and a cavity occurs. The cavity must then be cleaned and filled. It exists a lot of dental fillings, like gold, amalgam, ceramics or polymeric materials. After filling other dangers can occur: The mechanical properties of the materials used to fill cavities can differ strongly from the ones of the dental enamel itself. In the worst case, the filling of a tooth can damage the enamel of the opposite tooth by chewing if the interaction of enamel and filling is not equivalent, so that the harder fillings can abrade the softer enamel of the healthy tooth at the opposite side. This could be avoided if the anisotropic mechanical properties of dental enamel would be known in detail, hence then another filling could be searched or fabricated as an equivalent opponent for the dental enamel with equal properties. To find such a material, one has to characterise the properties of dental enamel first in detail for the different types of teeth (incisor, canine, premolar and molar). This is here exemplary done for a human incisor tooth by texture analysis with the program MAUD from 2D synchrotron transmission images [2,3,4].

scholarly journals Stress, strain and deformation of poly-lactic acid filament deposited onto polyethylene terephthalate woven fabric through 3D printing process

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Prisca Aude Eutionnat-Diffo ◽  
Yan Chen ◽  
Jinping Guan ◽  
Aurelie Cayla ◽  
Christine Campagne ◽  
...  
Keyword(s):  
Lactic Acid ◽  
3D Printing ◽  
Tensile Properties ◽  
Polyethylene Terephthalate ◽  
Polymeric Materials ◽  
Deposition Process ◽  
Woven Fabric ◽  
Poly Lactic Acid ◽  
Printing Process ◽  
3D Printed

Abstract Although direct deposition of polymeric materials onto textiles through 3D printing is a great technique used more and more to develop smart textiles, one of the main challenges is to demonstrate equal or better mechanical resistance, durability and comfort than those of the textile substrates before deposition process. This article focuses on studying the impact of the textile properties and printing platform temperature on the tensile and deformations of non-conductive and conductive poly lactic acid (PLA) filaments deposited onto polyethylene terephthalate (PET) textiles through 3D printing process and optimizing them using theoretical and statistical models. The results demonstrate that the deposition process affects the tensile properties of the printed textile in comparison with the ones of the textiles. The stress and strain at rupture of the first 3D printed PLA layer deposited onto PET textile material reveal to be a combination of those of the printed layer and the PET fabric due to the lower flexibility and diffusion of the polymeric printed track through the textile fabric leading to a weak adhesion at the polymer/textile interface. Besides, printing platform temperature and textile properties influence the tensile and deformation properties of the 3D printed PLA on PET textile significantly. Both, the washing process and the incorporation of conductive fillers into the PLA do not affect the tensile properties of the extruded polymeric materials. The elastic, total and permanent deformations of the 3D-printed PLA on PET fabrics are lower than the ones of the fabric before polymer deposition which demonstrates a better dimensional stability, higher stiffness and lower flexibility of these materials.

scholarly journals Fabrication of piezoelectric poly(l-lactic acid)/BaTiO3 fibre by the melt-spinning process

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hyun Ju Oh ◽  
Do-Kun Kim ◽  
Young Chan Choi ◽  
Seung-Ju Lim ◽  
Jae Bum Jeong ◽  
...  
Keyword(s):  
Phase Transition ◽  
Lactic Acid ◽  
Crystalline Phase ◽  
Melt Spinning ◽  
Piezoelectric Properties ◽  
Polymeric Materials ◽  
Processing Conditions ◽  
Post Processing ◽  
Scanning Calorimetry ◽  
Spinning Process

Abstract Poly(l-lactic acid) (PLLA) based piezoelectric polymers are gradually becoming the substitute for the conventional piezoelectric ceramic and polymeric materials due to their low cost and biodegradable, non-toxic, piezoelectric and non-pyroelectric nature. To improve the piezoelectric properties of melt-spun poly(l-lactic acid) (PLLA)/BaTiO3, we optimized the post-processing conditions to increase the proportion of the β crystalline phase. The α → β phase transition behaviour was determined by two-dimensional wide-angle x-ray diffraction and differential scanning calorimetry. The piezoelectric properties of PLLA/BaTiO3 fibres were characterised in their yarn and textile form through a tapping method. From these results, we confirmed that the crystalline phase transition of PLLA/BaTiO3 fibres was significantly enhanced under the optimised post-processing conditions at a draw ratio of 3 and temperature of 120 °C during the melt-spinning process. The results indicated that PLLA/BaTiO3 fibres could be a one of the material for organic-based piezoelectric sensors for application in textile-based wearable piezoelectric devices.

Structure and properties of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)/poly(L-lactic acid) quasi core/sheath melt-electrospun microfibers

2018 ◽  
Vol 89 (9) ◽  
pp. 1770-1781 ◽  
Author(s):  
Huaizhong Xu ◽  
Benedict Bauer ◽  
Masaki Yamamoto ◽  
Hideki Yamane
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Lactic Acid ◽  
Tensile Tests ◽  
Processing Parameters ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Diffraction Patterns

A facile route was proposed to fabricate core–sheath microfibers, and the relationships among processing parameters, crystalline structures and the mechanical properties were investigated. The compression molded poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH)/poly(L-lactic acid) (PLLA) strip enhanced the spinnability of PHBH and the mechanical properties of PLLA as well. The core–sheath ratio of the fibers was determined by the prefab strip, while the PLLA sheath component did not completely cover the PHBH core component due to the weak interfacial tension between the melts of PHBH and PLLA. A rotational target was applied to collect aligned fibers, which were further drawn in a water bath. The tensile strength and the modulus of as-spun and drawn fibers increased with increasing the take-up velocities. When the take-up velocity was above 500 m/min, the jet became unstable and started to break up at the tip of the Taylor cone, decreasing the mechanical properties of the fibers. The drawing process facilitated the crystallization of PLLA and PHBH, and the tensile strength and the modulus increased linearly with the increasing the draw ratio. The crystal information displayed from wide-angle X-ray diffraction patterns and differential scanning calorimetry heating curves supported the results of the tensile tests.

Sign in / Sign up

Export Citation Format

Share Document