X-ray diffraction studies on stress transfer of kenaf reinforced poly(l-lactic acid) composite

2006 ◽  
Vol 37 (12) ◽  
pp. 2269-2273 ◽  
Author(s):  
Takashi Nishino ◽  
Koichi Hirao ◽  
Masaru Kotera
Keyword(s):  
Lactic Acid ◽  
Stress Transfer ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals (S)-1-(Ethoxycarbonyl)ethyl(2R,5S)-2,5-dimethyl-1,3-dioxolan-4-one-2-carboxylate

Molbank ◽  
10.3390/m1178 ◽  
2021 ◽  
Vol 2021 (1) ◽  
pp. M1178
Author(s):  
R. Aitken ◽  
Oliver Haslett ◽  
Alexandra Slawin
Keyword(s):  
Lactic Acid ◽  
Title Compound ◽  
Ethyl Pyruvate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nmr Methods

The title compound was obtained in low yield in the condensation of ethyl pyruvate and lactic acid. Its structure is determined by NMR methods and x-ray diffraction and the mechanism for formation of this 1:2 adduct from the initial 1:1 adduct is considered.

scholarly journals Effect of Film Formation Method and Annealing on Crystallinity of Poly(L-Lactic Acid) Films

2011 ◽  
Author(s):  
Shan-Ting Hsu ◽  
Y. Lawrence Yao
Keyword(s):  
Drug Delivery ◽  
Lactic Acid ◽  
Film Formation ◽  
Solvent Casting ◽  
Crystalline Morphology ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lamellar Structures ◽  
Coating Methods ◽  
Formation Method

Poly(L-lactic acid) (PLLA) has been shown to have potential medical usage such as in drug delivery because it can degrade into bioabsorbable products in physiological environments, and its degradation is affected by crystallinity. In this paper, the effect of film formation method and annealing on the crystallinity of PLLA are investigated. The films are made through solvent casting and spin coating methods, and subsequent annealing is conducted. The resulting crystalline morphology, structure, conformation, and intermolecular interaction are examined using optical microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. It is observed that solvent casting produces category 1 spherulites while annealed spin coated films leads to spherulites of category 2. Distinct lamellar structures and intermolecular interactions in the two kinds of films have been shown. The results enable better understanding of the crystallinity in PLLA, which is essential for its drug delivery application.

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.

scholarly journals Hemp Fibre Reinforced Poly(Lactic Acid) Composites

2007 ◽  
Vol 29-30 ◽  
pp. 337-340 ◽  
Author(s):  
M.A. Sawpan ◽  
K.L. Pickering ◽  
Alan Fernyhough
Keyword(s):  
Lactic Acid ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Hemp Fibre ◽  
Reinforcing Material ◽  
Fibre Loading ◽  
The Degree Of Crystallinity

The potential of hemp fibre as a reinforcing material for Poly(lactic acid) (PLA) was investigated. Good interaction between hemp fibre and PLA resulted in increases of 100% for Young’s modulus and 30% for tensile strength of composites containing 30 wt% fibre. Different predictive ‘rule of mixtures’ models (e.g. Parallel, Series and Hirsch) were assessed regarding the dependence of tensile properties on fibre loading. Limited agreement with models was observed. Differential scanning calorimetry (DSC) and x-ray diffraction (XRD) studies showed that hemp fibre increased the degree of crystallinity in PLA composites.

Characterization of Electrospun Poly(Lactic Acid)/polyaniline Blend Nanofibers

2011 ◽  
Vol 332-334 ◽  
pp. 317-320 ◽  
Author(s):  
Hui Qin Zhang
Keyword(s):  
Lactic Acid ◽  
Composite Nanofibers ◽  
Weight Ratio ◽  
Electrospinning Process ◽  
Poly Lactic Acid ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Ft Ir

In this study, composite nanofibers of polyaniline doped with dodecylbenzene sulfonic acid (PANI-DBSA) and Poly(lactic acid) (PLA) were prepared via an electrospinning process. The surface morphology, thermal properties and crystal structure of PLA/PANI-DBSA nanofibers are characterized using Fourier transform infrared spectroscopy (FT-IR), wide-angle x-ray diffraction (WAXD) and scanning electron microscopy (SEM). SEM images showed that the morphology and diameter of the nanofibers were affected by the weight ratio of blend solution.

Effect of Laser Surface Modification on the Crystallinity of Poly(L-Lactic Acid)

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
Anubha Bhatla ◽  
Y. Lawrence Yao
Keyword(s):  
Lactic Acid ◽  
Polymer Surface ◽  
X Ray Diffraction ◽  
Factors Affecting ◽  
Laser Surface Modification ◽  
Third Harmonic ◽  
X Ray ◽  
Annealing Conditions ◽  
Kinetics Of

Crystallinity of semicrystalline polymers such as aliphatic homopolymer poly(L-lactic acid) (PLLA) affects their degradation and physical properties. In this paper, the effects of laser irradiation using the third harmonic of a Nd:YAG laser on the crystallinity, long-range order, and short-range conformations at the surface of PLLA films are investigated. The factors affecting the transformation are also studied. Detailed characterization of the effect of laser treatment is accomplished using microscopy, X-ray diffraction, and infrared spectroscopy. The cooling rates in the process and the spatial and temporal temperature profiles are numerically examined. The simulation results in conjunction with melting and crystallization kinetics of PLLA are used to understand the effect on sample crystallinity. The effects of laser fluence and annealing conditions on the crystallinity of the processed films are examined. Since degradation profiles depend on crystallinity, laser processing can potentially be used to achieve a modified spatially controlled polymer surface with promising applications such as controlled drug delivery.

Crystallization Properties of Nucleated Poly(lactic acid)

2012 ◽  
Vol 549 ◽  
pp. 322-326 ◽  
Author(s):  
Yong Chen ◽  
Qiang Dou
Keyword(s):  
Lactic Acid ◽  
Crystallization Behavior ◽  
Polarized Light ◽  
Nucleating Agent ◽  
Poly Lactic Acid ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Crystallization Properties ◽  
Melting And Crystallization

The effect of a nucleating agent (NT-C) on the crystallization behavior of poly(lactic acid) (PLA) was studied. The melting and crystallization behavior and spherulitic morphology of the nucleated PLA were investigated by means of differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and polarized light microscopy (PLM). It is found that the crystallization temperature and crystallinity increase, the spherulitic size decrease for the nucleated PLA. But the crystal structure of the nucleated PLA is not changed.

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