Synthesis and characterization of three different radiopaque thermoplastic polyurethane elastomers are reported. Radiopacity was introduced to the polyurethanes by incorporating an iodinated chain extender, namely, 4,4'-isopropylidinedi-(2,6-diiodophenol) (IBPA), into the polymer chain during polyurethane synthesis. Radiopaque polyurethanes (RPUs) were synthesized by reacting 4,4'-methylenebis(phenyl isocyanate) (MDI), IBPA, and three different diols. The polyols used for the synthesis were polypropylene glycol, polycaprolactone diol, and poly(hexamethylene carbonate) diol. RPUs were characterized by infrared spectroscopy, contact angle measurements, thermogravimetry, dynamic mechanical analysis, energy dispersive X-ray analysis, gel permeation chromatography, X-ray fluorescence spectroscopy, and X-radiography. X-ray images showed that all RPUs prepared using IBPA as the chain extender are highly radiopaque compared with an Aluminum wedge of equivalent thickness. Elemental analysis revealed that the polyurethanes contained 18-19% iodine in the polymer matrix. The RPUs developed have radiopacity equivalent to that of a polymer filled with 20 wt % barium sulfate. Results revealed that RPUs of wide range of properties may be produced by incorporating different diols as the soft chain segment. Cell culture cytotoxicity studies conducted using L929 cells by direct contact test and MTT assay proved that these RPUs are noncytotoxic in nature.
Poly(glycerol sebacate)
(PGS), produced from renewable monomers
such as sebacic acid and glycerol, has been explored extensively for
various biomedical applications. However, relatively less attention
has been paid to explore PGS as sustainable materials in applications
such as elastomers and rigid plastics, primarily because of serious
deficiencies in physical properties of PGS. Here, we present two new
approaches for enhancing the properties of PGS; (i) synthesizing block
copolymers of PGS with poly(tetramethylene oxide)glycol (PTMO) and
(ii) preparing a blend of PGS-b-PTMO with a poly(ester–ether)
thermoplastic elastomer. The consequence of molar ratio (hard and
soft segments) and Mn of soft segment
on tensile properties of the material was investigated. The PGS-b-PTMO with 25:75 mole ratios of hard and soft segments
and having a medium Mn soft segment (5350
g mol–1) exhibits an appreciable increase in percentage
of elongation that is from 32% for PGS to 737%. Blends of PGS-b-PTMO and a thermoplastic polyester elastomer, Hytrel 3078,
form a semi-interpenetrated polymer network, which exhibits increased
tensile strength to 2.11 MPa and percentage of elongation to 2574.
An elongation of such magnitude is unprecedented in the literature
for predominantly aliphatic polyesters and demonstrates that the simple
polyester can be tailored for superior performance.
Graphene
family materials (GFMs) are extensively explored for various
biomedical applications due to their unique physical properties. The
prime challenge is to establish a conclusive safety profile of these
nanomaterials and their respective products or devices. Formulating
GFMs with appropriate ingredients (e.g., surfactant/compatibilizer)
will help to disperse them homogeneously (i.e., within the polymer
matrix in the case of polymer–graphene nanocomposites) and
aid in good interfacial interaction to achieve the desired properties.
However, no cytotoxicity report is available on the effects of the
additives on graphene and its incorporated materials. Here, we report
in vitro cytotoxicity of formulated FLG (FLG-C), i.e., a mixture of
FLG, melamine, and sodium poly(naphthalene sulfonate) (SPS), along
with natural rubber (NR) latex and FLG-C-included NR latex nanocomposite
(FLG-C-NR) thin films on human vaginal epithelial (HVE) cells. FLG-C
shows reduced cellular proliferation (∼55%) only at a longer
exposure time (72 h) even at a low concentration (50 μg/mL).
It also displays significant down- and upregulation in mitochondrial
membrane potential (MMP) and reactive oxygen species (ROS), respectively,
whereas no changes are observed in lactate dehydrogenase (LDH), propidium
iodide (PI), uptake, and cell cycle analysis at 48 h. In vitro experiments
on NR latex and FLG-C-NR latex thin films demonstrate that the incorporation
of FLG-C does not compromise the biocompatibility of the NR latex.
Further substantiation from the in vivo experiments on the thin films
recommends that FLG-C could be suitable to prepare a range of biocompatible
rubber latex nanocomposites-based products, viz., next-generation
condoms (male and female), surgical gloves, catheters, vaginal rings,
bladder–rectum spacer balloon, etc.
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