scholarly journals Insights into the structural dynamics of poly lactic-co-glycolic acid at terahertz frequencies

2019 ◽  
Vol 10 (3) ◽  
pp. 351-361 ◽  
Author(s):  
Talia A. Shmool ◽  
J. Axel Zeitler

The mechanical properties of an amorphous copolymer are directly related to the dynamic processes occurring at the molecular level.

2013 ◽  
Vol 25 (46) ◽  
pp. 6724-6729 ◽  
Author(s):  
Jaewon Hwang ◽  
Taeshik Yoon ◽  
Sung Hwan Jin ◽  
Jinsup Lee ◽  
Taek-Soo Kim ◽  
...  

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 249
Author(s):  
Han-Seung Ko ◽  
Sangwoon Lee ◽  
Doyoung Lee ◽  
Jae Young Jho

To enhance the mechanical strength and bioactivity of poly(lactic acid) (PLA) to the level that can be used as a material for spinal implants, poly(glycolic acid) (PGA) fibers and hydroxyapatite (HA) were introduced as fillers to PLA composites. To improve the poor interface between HA and PLA, HA was grafted by PLA to form HA-g-PLA through coupling reactions, and mixed with PLA. The size of the HA particles in the PLA matrix was observed to be reduced from several micrometers to sub-micrometer by grafting PLA onto HA. The tensile and flexural strength of PLA/HA-g-PLA composites were increased compared with those of PLA/HA, apparently due to the better dispersion of HA and stronger interfacial adhesion between the HA and PLA matrix. We also examined the effects of the length and frequency of grafted PLA chains on the tensile strength of the composites. By the addition of unidirectionally aligned PGA fibers, the flexural strength of the composites was greatly improved to a level comparable with human compact bone. In the bioactivity tests, the growth of apatite on the surface was fastest and most uniform in the PLA/PGA fiber/HA-g-PLA composite.


2016 ◽  
Vol 36 (4) ◽  
pp. 399-405 ◽  
Author(s):  
Khalid Nawaz ◽  
Muhammad Ayub ◽  
Noaman Ul-Haq ◽  
M.B. Khan ◽  
Muhammad Bilal Khan Niazi ◽  
...  

Abstract Large area graphene oxide sheets were synthesized, dispersed in water and used as nanofiller for mechanical improvement in terms of Young’s modulus and ultimate tensile strength (UTS) of polyvinyl alcohol (PVA) at low loading. The molecular level dispersion and interfacial interactions between the graphene oxides and polymeric matrix PVA were the real challenges. An excellent improvement in mechanical properties at 0.35 wt% loading was observed. Modulus improved from 1.58 GPa to 2.72 GPa (~71% improvement), UTS improved from 120 MPa to 197 MPa (~65% improvement), and in spite of these improvements, interestingly, there was no fall in elongation at break at this loading.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Débora Pereira Diniz Correia Barcellos ◽  
Ana Paula Farina ◽  
Ramiro Barcellos ◽  
Matheus Albino Souza ◽  
Márcia Borba ◽  
...  

Physiology ◽  
2005 ◽  
Vol 20 (1) ◽  
pp. 43-53 ◽  
Author(s):  
Brian P. Helmke

The endothelium at the interface between blood and tissue acts as a primary transducer of local hemodynamic forces into signals that maintain physiological function or initiate pathological processes in vessel walls. Rapid intracellular spatial gradients of structural dynamics and signaling molecule activity suggest that mechanical cues at the molecular level guide cellular mechanotransduction and adaptation to shear stress profiles.


Author(s):  
E.A.C Johnson ◽  
R.H.C Bonser ◽  
G Jeronimidis

The importance of biological materials has long been recognized from the molecular level to higher levels of organization. Whereas, in traditional engineering, hardness and stiffness are considered desirable properties in a material, biology makes considerable and advantageous use of softer, more pliable resources. The development, structure and mechanics of these materials are well documented and will not be covered here. The purpose of this paper is, however, to demonstrate the importance of such materials and, in particular, the functional structures they form. Using only a few simple building blocks, nature is able to develop a plethora of diverse materials, each with a very different set of mechanical properties and from which a seemingly impossibly large number of assorted structures are formed. There is little doubt that this is made possible by the fact that the majority of biological ‘materials’ or ‘structures’ are based on fibres and that these fibres provide opportunities for functional hierarchies. We show how these structures have inspired a new generation of innovative technologies in the science and engineering community. Particular attention is given to the use of insects as models for biomimetically inspired innovations.


2016 ◽  
Vol 45 (17) ◽  
pp. 4797-4824 ◽  
Author(s):  
Luis M. De Leon Rodriguez ◽  
Yacine Hemar ◽  
Jillian Cornish ◽  
Margaret A. Brimble

This review discusses about β-sheet peptide structure at the molecular level and the bulk mechanical properties of the corresponding hydrogels.


2017 ◽  
Vol 529 (1-2) ◽  
pp. 371-380 ◽  
Author(s):  
X. Liu ◽  
J. Aho ◽  
S. Baldursdottir ◽  
A. Bohr ◽  
H. Qu ◽  
...  

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