Effect of accelerated aging on the cross-link density of medical grade silicones.

Biomed Mater Eng

School of Engineering, Department of Mechanical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.

Published: November 2016

Four specimens of Nagor silicone of different hardness (soft, medium and hard) were swollen, until they reached equilibrium (i.e. constant mass) in five liquids at 25°C, before and after accelerated aging. For the specimens swollen before accelerated aging, the greatest swelling was obtained in methyl cyclohexane, while for the specimens swollen after accelerated aging, the greatest swelling was obtained in cyclohexane. The cross-link density, υ, was also calculated from the swelling measurements for all the specimens, before and after accelerated aging, using the Flory-Rehner equation. The softer silicones, which swelled the most, had lower υ values than harder silicones. The amount of swelling (measured in terms of ϕ) and υ varied significantly (p<0.05) in some cases, between the different silicone hardness and between different liquids. Furthermore, the cross-link density, υ, significantly (p<0.05) increased after accelerated aging in most liquids.Note: ϕ is defined as the volume fraction of polymer in its equilibrium swollen state. A probability value of statistical significance of 0.05 or 5% was selected, hence if a p value of less than 0.05 was obtained, the null hypothesis was rejected (i.e. significant if p<0.05).

Download full-text PDF

Source
http://dx.doi.org/10.3233/BME-161598DOI Listing

Publication Analysis

Top Keywords

accelerated aging
20
cross-link density
8
specimens swollen
8
swollen accelerated
8
aging greatest
8
greatest swelling
8
accelerated
5
aging cross-link
4
density medical
4
medical grade
4

Similar Publications

Age differences in brain hemispheric asymmetry have figured prominently in the neuropsychology of aging. Here, a broad overview of these empirical and theoretical approaches is provided that dates back to the 1970s and continues to the present day. Methodological advances often brought new evidence to bear on older ideas and promoted the development of new ones.

View Article and Find Full Text PDF

Background: Biological age serves as a common starting point for various age-related diseases and can be associated with a wide range of cardiovascular outcomes. However, associations between cardiovascular biological age (CBA) and various types of cardiovascular disease (CVD) remain unclear.

Methods And Results: Analyzing 262,343 UK Biobank participants, we constructed CBA based on composite biomarkers using the Klemera-Doubal method (denoted as KDM-CBA).

View Article and Find Full Text PDF

Transient receptor potential ankyrin 1 (TRPA1) is a sensory channel expressed in vagal afferent nerves that detect noxious stimuli. Trpa1 knockout accelerates age-related cardiac fibrosis and dysfunction in mice. This study investigated whether TRPA1 activation with its selective agonist, allyl isothiocyanate (AITC), prevents cardiac aging.

View Article and Find Full Text PDF

Age-related alterations in the skeletal system are linked to decreased bone mass, a reduction in bone strength and density, and an increased risk of fractures and osteoporosis. Therapeutics are desired to stimulate bone regeneration and restore imbalance in the bone remodeling process. Quercetin (Qu), a naturally occurring flavonoid, induces osteogenesis; however, its solubility, stability, and bioavailability limit its therapeutic use.

View Article and Find Full Text PDF

Investigating the Degradation of Historical Man-Made Cellulose-Derived Textiles via Accelerated Ageing.

Chempluschem

March 2025

University College London, The Bartlett School of Environment Energy and Resources, University College London, 14 Upper Woburn Place, WC1H 0NN, London, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND.

Cellulose-derived materials, like paper and cellulose acetate, are known to be vulnerable to degradation within museum collections. Studies have been conducted and degradation markers have been identified on these materials. However, the degradation of man-made cellulose-derived fibres in collections is not well understood.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!