Comb-Shaped Conjugates Comprising Hydroxypropyl Cellulose Backbones and Low-Molecular-Weight Poly(N-isopropylacryamide) Side Chains for Smart Hydrogels: Synthesis, Characterization, and Biomedical Applications

2010 ◽  
Vol 21 (3) ◽  
pp. 456-464 ◽  
Author(s):  
F. J. Xu ◽  
Y. Zhu ◽  
F. S. Liu ◽  
J. Nie ◽  
J. Ma ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Biomedical Applications ◽  
Hydroxypropyl Cellulose ◽  
Low Molecular Weight ◽  
Side Chains

The Velocity of Propagation of Ultrasonic Waves and the Form of the Molecules of High Polymers

1950 ◽  
Vol 23 (1) ◽  
pp. 151-162
Author(s):  
Giulio Natta ◽  
Mario Baccaredda
Keyword(s):  
Molecular Weight ◽  
Form Factor ◽  
Experimental Error ◽  
Ultrasonic Waves ◽  
Low Molecular Weight ◽  
Side Chains ◽  
Polyethylene Oxides ◽  
Velocity Of Propagation ◽  
Secondary Side ◽  
Linear Macromolecules

Abstract The velocity of propagation of ultrasonic waves in numerous substances of high molecular weight was determined. For substances not fusible at temperatures below 100° C, this velocity was determined by extrapolation from solutions considered ideal. For linear macromolecules without side chains, the ultrasonic velocity appears to be practically equal, within the limits of experimental error, to that calculated by the formula of Rao and on a basis of the additive values of the bond velocity of Lagemann and Corry. For molecules which have many side chains, the velocity is lower than the calculated value, whereas for compounds of low molecular weight this deviation is relatively small, viz., less than 10 per cent; it becomes much higher, viz., almost up to 40 per cent, for macromolecules. The form factor is defined as the ratio of the velocity determined experimentally to the velocity calculated by the formula of Rao. This form factor is equal to 1 for polymers without side chains or with very few side chains, such as paraffins, polyethylenes, Nylon, polyethylene oxides, and polyoxymethylenes; is only 0.89–0.90 for natural rubber; only 0.82–0.84 for Buna and for hydrogenated Buna, poly-α-butylenes, and polystyrenes; only 0.79–0.80 for polyisobutylenes; only 0.89 for polymethacrylates; only 0.78 for polyvinylisobutyl ethers; only 0.65 for Butyl rubber; and only 0.63 for polymethyl methacrylates. The form factor is thus affected by the frequency and length of the side chains, and by any secondary side chains which may be present.

Production of oxygen-15, nitrogen-13 and carbon-11 and of their low molecular weight derivatives for biomedical applications

1979 ◽  
Vol 30 (9) ◽  
pp. 543-549 ◽  
Author(s):  
Guy Del Fiore ◽  
Jean-Claude Depresseux ◽  
P. Bartsch ◽  
Lino Quaglia ◽  
Jean-Marie Peters
Keyword(s):  
Molecular Weight ◽  
Biomedical Applications ◽  
Low Molecular Weight

Thermal and Liquid Crystalline Properties of a Polymer with Amphiphilic-Mesogenic Side-Chains

2001 ◽  
Vol 709 ◽  
Author(s):  
Seiji Ujiie ◽  
Yumi Yano ◽  
Akira Mori
Keyword(s):  
Molecular Weight ◽  
Liquid Crystalline ◽  
Water Soluble ◽  
Low Molecular Weight ◽  
Side Chains ◽  
Columnar Phase ◽  
Smectic A ◽  
Smectic C ◽  
Heating And Cooling ◽  
Lyotropic Mesophases

ABSTRACTA low-molecular-weight liquid crystalline amphiphilic compound (Az6Bu) and a liquid crystalline polymethacrylate [P(Az6Bu)] with amphiphilic-mesogenic side-chains are reported in this present paper. A polyethyleneimine chain with 2-hydroxyethyl side-groups was used as the water-soluble spacer. Az6Bu exhibited a lyotropic columnar phase and no thermotropic mesophase. P(Az6Bu) showed thermotropic and lyotropic liquid crystalline properties. P(Az6Bu) formed thermotropic smectic A and C mesophases on the heating and cooling processes. The lyotropic systems consisting of P(Az6Bu) and water exhibited a smectic C lyomesophase with oilystreak and schlieren textures. The layered structures formed in the thermotropic and lyotropic mesophases are composed of a sublayer produced by the anisotropic alignment of aromatic-mesogenic groups and a sublayer of hydrophilic groups.

Determination of the pattern of acetylation of low-molecular-weight chitosan used in biomedical applications

2009 ◽  
Vol 50 (4) ◽  
pp. 587-590 ◽  
Author(s):  
Jolanta Kumirska ◽  
Mirko X. Weinhold ◽  
Janelle C.M. Sauvageau ◽  
Jorg Thöming ◽  
Zbigniew Kaczyński ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Biomedical Applications ◽  
Low Molecular Weight ◽  
Low Molecular Weight Chitosan

scholarly journals Low Molecular Weight and Polymeric Modifiers as Toughening Agents in Poly(3-Hydroxybutyrate) Films

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2446
Author(s):  
Adriana Nicoleta Frone ◽  
Cristian Andi Nicolae ◽  
Mihaela Carmen Eremia ◽  
Vlad Tofan ◽  
Marius Ghiurea ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Photoelectron Spectroscopy ◽  
Biomedical Applications ◽  
Low Molecular Weight ◽  
Elongation At Break ◽  
Force Microscopy ◽  
In Vitro Biocompatibility ◽  
Atomic Force ◽  
Lower Temperature

The inherent brittleness of poly(3-hydroxybutyrate) (PHB) prevents its use as a substitute of petroleum-based polymers. Low molecular weight plasticizers, such as tributyl 2-acetyl citrate (TAC), cannot properly solve this issue. Herein, PHB films were obtained using a biosynthesized poly(3-hydroxyoctanoate) (PHO) and a commercially available TAC as toughening agents. The use of TAC strongly decreased the PHB thermal stability up to 200 °C due to the loss of low boiling point plasticizer, while minor weight loss was noticed at this temperature for the PHB-PHO blend. Both agents shifted the glass transition temperature of PHB to a lower temperature, the effect being more pronounced for TAC. The elongation at break of PHB increased by 700% after PHO addition and by only 185% in the case of TAC; this demonstrates an important toughening effect of the polymeric modifier. Migration of TAC to the upper surface of the films and no sign of migration in the case of PHO were highlighted by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) results. In vitro biocompatibility tests showed that all the PHB films are non-toxic towards L929 cells and have no proinflammatory immune response. The use of PHO as a toughening agent in PHB represents an attractive solution to its brittleness in the case of packaging and biomedical applications while conserving its biodegradability and biocompatibility.

Synthesis and evaluation of chiral β-amino acid-based low-molecular-weight organogelators possessing a methyl/trifluoromethyl side chain

2019 ◽  
Vol 43 (7) ◽  
pp. 2882-2887 ◽  
Author(s):  
Koichi Kodama ◽  
Ryuta Kawamata ◽  
Takuji Hirose
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Amino Acid ◽  
Supramolecular Structures ◽  
Side Chain ◽  
Low Molecular Weight ◽  
Side Chains ◽  
Low Molecular Weight Organogelators

Impacts of side-chains and chirality of organogelators derived from β-amino acids are described with their supramolecular structures.

Material-assisted mass spectrometric analysis of low molecular weight compounds for biomedical applications

2021 ◽  
Author(s):  
Anuja Shreeram Kulkarni ◽  
Lin Huang ◽  
Kun Qian
Keyword(s):  
Molecular Weight ◽  
Biomedical Applications ◽  
Physiological State ◽  
High Sensitivity ◽  
Spectrometric Analysis ◽  
Low Molecular Weight ◽  
Ionization Mass ◽  
Laser Desorption Ionization ◽  
Low Molecular Weight Compounds ◽  
Low Costs

Low molecular weight compounds play an important role in encoding the current physiological state of an individual. Laser desorption/ionization mass spectrometry (LDI MS) offers high sensitivity with low costs for...

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