Rheological characterization of biocompatible associative polymer hydrogels with crystalline and amorphous endblocks

2006 ◽  
Vol 21 (8) ◽  
pp. 2118-2125 ◽  
Author(s):  
Sarvesh K. Agrawal ◽  
Naomi Sanabria-DeLong ◽  
Gregory N. Tew ◽  
Surita R. Bhatia
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Elastic Modulus ◽  
Block Length ◽  
Rheological Characterization ◽  
Precise Control ◽  
Order Of Magnitude ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

Control over mechanical properties of hydrogels is of primary importance for the use of these materials in drug delivery and tissue engineering applications. We demonstrate here that crystallinity and block length of poly(lactide) (PLA) can be used to tune the elastic modulus of associative network gels of poly(lactide)–poly(ethylene oxide)–poly(lactide) over several orders of magnitude. Polymers made with crystalline L lactic acid blocks formed very stiff hydrogels at 25 wt% concentration with an elastic modulus that was almost an order of magnitude higher than hydrogels of polymers with a similar molecular weight but containing amorphous D/L-lactic acid blocks. The relaxation behavior and crosslink density of gels are also significantly influenced by crystallinity of PLA and are again a function of PLA block length. Using these variables we can design new tailor-made materials for biomedical applications with precise control over their structure and mechanical properties.

scholarly journals Processing of Sr2+ Containing Poly L-Lactic Acid-Based Hybrid Composites for Additive Manufacturing of Bone Scaffolds

2020 ◽  
Vol 7 ◽  
Author(s):  
Priscila Melo ◽  
Raasti Naseem ◽  
Ilaria Corvaglia ◽  
Giorgia Montalbano ◽  
Carlotta Pontremoli ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Additive Manufacturing ◽  
Hybrid Composites ◽  
Homogeneous Distribution ◽  
Fused Filament Fabrication ◽  
Rheological Characterization ◽  
Biodegradable Composite ◽  
Manufacturing Technologies

Biodegradable composite materials represent one of the major areas of investigation for bone tissue engineering due to their tuneable compositional and mechanical properties, which can potentially mimic those of bone and potentially avoid the removal of implants, mitigating the risks for the patient and reducing the overall clinical costs. In addition, the introduction of additive manufacturing technologies enables a strict control over the final morphological features of the scaffolds. In this scenario, the optimisation of 3D printable resorbable composites, made of biocompatible polymers and osteoinductive inorganic phases, offers the potential to produce a chemically and structurally biomimetic implant, which will resorb over time. The present work focuses on the development and process optimisation of two hybrid composite filaments, to be used as feedstock for the fused filament fabrication 3D printing process. A Poly L-lactic acid matrix was blended with either rod-like nano-hydroxyapatite (nano-HA) or nanoparticles of mesoporous bioactive glasses, both partially substituted with strontium (Sr2+), due to the well-known pro-osteogenic effect of this ion. Both inorganic phases were incorporated into Poly L-lactic acid using an innovative combination of processes, obtaining a homogeneous distribution throughout the polymer whilst preserving their ability to release Sr2+. The filament mechanical properties were not hindered after the incorporation of the inorganic phases, resulting in tensile strengths and moduli within the range of cancellous bone, 50 ± 10 MPa and 3 ± 1 GPa. Finally, the rheological characterization of the hybrid composites indicated a shear thinning behaviour, ideal for the processing with fused filament fabrication, proving the potential of these materials to be processed into 3D structures aiming bone regeneration.

scholarly journals Effect of uniaxial pre-stretching on the microstructure and mechanical properties of poly[(ethylene oxide)-block-(amide-12)]-toughened poly(lactic acid) blend

RSC Advances ◽  
2017 ◽  
Vol 7 (2) ◽  
pp. 712-719 ◽  
Author(s):  
Yunjing Chen ◽  
Lijing Han ◽  
Zonglin Li ◽  
Junjun Kong ◽  
Dandan Wu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Ethylene Oxide ◽  
Mechanical Strength ◽  
Poly Lactic Acid ◽  
Microstructure And Mechanical Properties ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

The mechanical strength of the pre-stretched blend was dramatically improved without too much sacrifice of the toughness.

Processing and characterization of poly(ethylene oxide)/clay nanocomposites

2011 ◽  
Vol 31 (4) ◽  
Author(s):  
Debdatta Ratna
Keyword(s):  
Mechanical Properties ◽  
Ethylene Oxide ◽  
Solid Polymer Electrolytes ◽  
Solid Polymer ◽  
Clay Nanocomposites ◽  
Processing Temperature ◽  
Melt Mixing ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

Abstract In recent years, poly(ethylene oxide) (PEO) has gained two very important applications namely: 1) as solid polymer electrolytes for use in battery, supercapacitor and fuel cell, 2) as a crystallizable switching segment for shape memory polymer (SMP) systems. The common problem for all the applications is linked with the poor mechanical properties of PEO. Hence nanoreinforcement of PEO has been investigated to develop PEO based materials suitable for various applications. PEO/clay nanocomposites have been made by using a solution intercalation method or a melt mixing route. The nanocomposites were characterized by X-ray diffraction (XRD) and evaluated for their rheological and dynamic mechanical properties, Since PEO is sensitive to thermo-oxidative degradations, the effect of processing temperature on rheological properties was also investigated. The detailed processing and characterization of PEO/clay nanocomposites will be discussed in the present paper.

Characterization of Electrical and Mechanical Properties for Coaxial Nanofibers with Poly(ethylene oxide) (PEO) Core and Multiwalled Carbon Nanotube/PEO Sheath

2008 ◽  
Vol 41 (7) ◽  
pp. 2509-2513 ◽  
Author(s):  
Satyajeet S. Ojha ◽  
Derrick R. Stevens ◽  
Kelly Stano ◽  
Torissa Hoffman ◽  
Laura I. Clarke ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotube ◽  
Ethylene Oxide ◽  
Multiwalled Carbon Nanotube ◽  
Multiwalled Carbon ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene
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