Effects of lactic acid and mixed acid aqueous solutions on the preparation, structure and properties of thermoplastic chitosan

2020 ◽  
Vol 134 ◽  
pp. 109850
Author(s):  
Xiaoya Dou ◽  
Qian Li ◽  
Qiangxian Wu ◽  
Liansheng Duan ◽  
Shiyi Zhou ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Aqueous Solutions ◽  
Structure And Properties ◽  
Mixed Acid

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,...

Aqueous solutions of poly-N-alkyl-substituted acrylamides: Structure and properties related to targeted transport

1995 ◽  
Vol 67 (6) ◽  
pp. 963-968 ◽  
Author(s):  
L. I. Valuev ◽  
V. V. Chupov ◽  
O. N. Zefirova ◽  
T. L. Lebedeva ◽  
N. A. Platé
Keyword(s):  
Aqueous Solutions ◽  
Structure And Properties ◽  
Targeted Transport

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.

Structure and properties of iron(III) 1,3-propanediaminetetraacetate complex in aqueous solutions

1991 ◽  
Vol 186 (2) ◽  
pp. 205-208 ◽  
Author(s):  
Kan Kanamori ◽  
Naoya Ukita ◽  
Kiyoyasu Kawai ◽  
Shigeru Taguchi ◽  
Katsumi Goto ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Structure And Properties

In vitro studies on the structure and properties of silk fibroin aqueous solutions in silkworm

2013 ◽  
Vol 62 ◽  
pp. 162-166 ◽  
Author(s):  
Yuan Jin ◽  
Yichun Hang ◽  
Jie Luo ◽  
Yaopeng Zhang ◽  
Huili Shao ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Silk Fibroin ◽  
In Vitro Studies ◽  
Structure And Properties

scholarly journals The diffusion of oxygen and lactic acid through tissues

1928 ◽  
Vol 104 (728) ◽  
pp. 39-96 ◽  
Keyword(s):  
Lactic Acid ◽  
Aqueous Solutions ◽  
Nerve Fiber ◽  
Living Cell ◽  
Diffusion Constant ◽  
Fatigued Muscle ◽  
Single Nerve ◽  
Capillary Circulation ◽  
Determining Factor

The diffusion of dissolved substances through cells and tissues is a determining factor in many vital processes. The slowness of diffusion on the scale of ordinary sensible objects gives to the unaided imagination an imperfect realisation of its speed and importance in systems of the dimensions of the living cell. The diffusion constant k is expressed in terms of the number of unit quantities of substance which diffuse per minute across an area of 1 sq. cm. in a gradient of concentration per cm. of 1 unit quantity per c. c. For aqueous solutions of ordinary substances k is usually of the order of 2 to 10 times 10 -4 . The diffusion constant is of the dimensions L 2 T -1 , 2 in length, -1 in time. Expressing it in units of 1μ (0·0001 cm.) instead of 1 cm., and of 1σ (0·001 sec.) instead of minutes, k is of the order of unity, instead of multiple of 10 -4 . Thus the diffusion constant is a fairly large quantity for systems involving distances of the order of 1μ and times of the order of 1σ. A cylinder 1 cm. in diameter composed of material similar to frog's nerve, if suddenly placed in oxygen, would take 185 minutes to attain 90 per cent. of is full saturation with that gas. An actual nerve 0·7 mm. thick would take 54 seconds for the same stage of saturation to be reached. A single nerve fiber 7μ thick would take only 5·4 σ. Again, the rapidity of diffusion attainable in systems of small dimensions is the basis of the capillary circulation, and therewith of the whole design of the larger animals; and the rate at which diffusion an supply oxygen to a fatigued muscle for the removal of lactic acid is an important factor in determining the speed at which recovery can occur.

Reactive extraction of 3-hydroxypropionic acid from model aqueous solutions and real bioconversion media. Comparison with its isomer 2-hydroxypropionic (lactic) acid

2015 ◽  
Vol 91 (8) ◽  
pp. 2276-2285 ◽  
Author(s):  
Marwen Moussa ◽  
Grégoire Burgé ◽  
Florian Chemarin ◽  
Rana Bounader ◽  
Claire Saulou-Bérion ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Aqueous Solutions ◽  
Reactive Extraction ◽  
Media Comparison ◽  
Hydroxypropionic Acid
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