Iranian Polymer Journal / Volume 9 Number 2 (2000) ISSN: 1026-1265/2000
Cartilage
Tissue Engineering for Ear as in Rabbit Model with
Perforated Polyurethane Prosthesis: In Vivo Assay
Hamid
Mirzadeh1(*),
M. Ali Mohagheghi2(*), Hossein Ahmadi2, Hamid Mirkhani2,
Saeed
Amanpour3 and Pirooz Salehian4
(1)
Iran Polymer Institute, P.O. Box 14965/159, Tehran, I.R. Iran
(2)
Cancer Institute, P.O. Box 13145-158, Tehran, I.R. Iran
(3)
Razi Vaccine and Serum Research Institute, Karaj, I.R. Iran
(4) Iran University of Medical Sciences, Tehran, I.R. Iran
Received 14 February 2000;
accepted 24 April 2020
ABSTRACT
Attempts have been done in this study to assay in vivo
implantation of the perforated polyurethane prosthesis as ear cartilage in a
rabbit model. The suitable prosthesis, compatible with ear cartilage in rabbit
(300–400 mm thickness) was synthesized and
implanted in the left ear of 18 rabbits as cartilage substitution. Cartilage
from the left ear with the same area of the implant was trans‑implanted on the
right ear as control. After 1 to 5.5 months en bloc resection of prosthesis and
surrounding tissues for histopathological and biocompatibility studies were
performed. Of the 18 inserted implants, complete healing was observed in 8
(45%) cases. Four (22%) of the remain-ing 10 implants showed partial healing
and remaining six (33%) showed non-healing. It was, therefore, concluded that
perforation might improve the cartilage cell ingrowth, when perforated
polyurethane used as artificial cartilage for the repair of ear cartilage
defects.
Key Words:
perforated polyurethane (PPU), biocompatibility, ear cartilage, tissue
engineering
Iranian Polymer Journal / Volume 9 Number 2 (2000) ISSN: 1026-1265/2000
Compounds
of Styrene-butadiene Rubber
M. Ali
Ansarifar*, Jatinder P. Chugh and Siavash Haghighat
Institute of Polymer Technology and
Materials Engineering, Loughborough University, Loughborough
Leicestershire LE11 3TU, UK
Received 13
December 1999; accepted 2 May 2020
ABSTRACT
The cure properties of
some conventional accelerator/sulphur compounds of styrene-butadiene rubber
(SBR) with a sulphur to accelerator ratio of ~1.8, containing no filler, and
10, 30, or 50 pphr rubber by weight precipitated amorphous white silica filler
type VN3 were studied at 160 ºC by an oscillating disc rheometer
curemeter. The optimum cure time, t95, of the compounds was
lengthened substantially from 20 to 280 min when silica loading was raised to
50 pphr. The rate of cure calculated from the cure rate index, decreased
sharply from 8.3 to 0.37 min–1 when the amount of silica in the
mixes reached 50 pphr. Interestingly, the scorch time, ts2, of the
compounds was not affected by the addition and increases in the amount of
silica, and remained at about 8 min, although, there was some evidence that silica
had interfered with the reaction mechanism of sulphur cure and reduced the
extent of cure in the rubbers. Our results indicated that the compounds were
fully cured when sufficient time i.e., up to 300 min for the mix with 50 pphr
filler, was allowed for the reaction in the compounds at elevated temperature
to complete.
Key Words: silica, styrene-butadiene rubber, accelerator/sulphur cure compounds, cure properties
Iranian Polymer Journal / Volume 9 Number 2 (2000) ISSN: 1026-1265/2000
Use of Rice Husk
and Phenols Extracted from it as Filler and
A.P. Kuriakose*
and G. Rajendran**
Department of
Polymer Science and Rubber Technology, Cochin University of Science and
Technology
Cochin‑682 022, India
Received 15 August 1998; accepted 29 November 2020
ABSTRACT
In
the present study, the rice husk is used as filler in natural rubber (NR) to
observe its reinforcing effect
on the rubber vulcanization. The effect of variation of particle size and of
filler loading is investigated. The results of the study indicated that much
reinforcement is not obtained by the incorporation of husk in different
formulations. When used in smaller particle size, however, some reinforcement
effect is noticed. This effect can further be increased by incorporation of
resorcinol and hexamine in the compound recipe. In the next part of the study,
the mixture of phenols consisting of ferulic, vanillic, p-coumaric,
sinapic p‑hydroxy benzoic, salicylic and indoleacetic acid extracted
from rice husk has been tried as antioxidant in NR gum and filled
vul-canizates. The results obtained were compared with those of control mixes
containing styrenated phenol. The cure characterisitics and vulcanizate
pro-perties were evaluated. The results indicated that there is not much
variation in cure characteristics or tensile properties between control and
experimental sets. Further, the antioxidant protection given by phenols from
rice husk is comparable with that of styrenated phenol.
Key Words: rice husk, phenol, filler, antioxidant, natural rubber
Iranian Polymer Journal / Volume 9 Number 2 (2000) ISSN: 1026-1265/2000
Polyurethanes (III): Polyaddition Products of
4,4´‑Bis(2-hydroxyethylenethio)diphenyl Ether and 2,4‑Tolylene
Diisocyanate
Danuta Wdowicka*,
Wawrzyniec Podkościelny and Anna Kultys
Department of Organic Chemistry and Technology, Maria Curie Skłodowska University 20‑614 Lublin, Poland
Received 8 November 1999; accepted 10 April 2020
ABSTRACT
New
linear polyurethanes derived from 4,4´‑bis(2-hydroxyethylenethio)di-phenyl
ether (4‑HETE) and 2,4‑tolylene diisocyanate (TDI) were synthesized by both
melt or solution polymerization. Good results were obtained using aprotic
solvent: N,N´-dimethylformamide, dibutyltin dilaurate (DLDBT) as a
catalyst ~1 wt % concentration and ~30 wt % concentration of monomers and
conducting the process at 90–100 ºC for 2 h. Basic physico‑chemical
properties of the series of PUs obtained are presented. Thermal properties of
the polymers were investigated by means of thermal gravimetric analysis (TGA)
and differential scanning calorimetry (DSC). Molecular weight distribution was
determined by gel permeation chromatography. The structure of the resulting
products was confirmed by elemental analysis, Fourier transform infra-red
spectroscopy and X‑ray diffractometry. The properties of copolyurethanes
containing variable amounts of poly(oxytetramethylene)diol (PTMO~650 or 1000)
synthesized in the conditions established earlier for non-segmented PUs are
also presented.
Key Words: linear polyurethanes, polyaddition, non-segmented polyurethanes, segmented polyurethanes, characterization
Iranian Polymer Journal / Volume 9 Number 2 (2000) ISSN: 1026-1265/2000
Ashish P. Naik1, Kishore R.
Desai1(*), Hasmukh S. Patel2
(1) Department of Chemistry, South
Gujarat University, Surat‑395 007, Gujarat, India
(2) Department of Chemistry, S.P.
University, Vallabh Vidhyanagar, India
Received 21
September 1999; accepted 2 April 2020
ABSTRACT
Resorcinol-formaldehyde
oligomer was synthesized by the condensation of resorcinol and formaldehyde in
presence of oxalic acid. The mole ratio of reactants employed was 1:0.5,
respectively. A series of new oligomeric disperse dyes were prepared by
coupling various aromatic diazonium salts to resorcinol‑formaldehyde oligomer.
Their dyeing on polyester, nylon and wool resulted in variety of attractive
hues on fibres. In this study of oligomeric azo- resorcinol‑formaldehyde dyes,
the dyeing of the fibres completed in short time and most important is that no
patches were observed on the fibres, while the earlier reported oligomeric dyes
form patches on the fibres. They were characterized in terms of their softening
points, colour, solubility, IR and UV visible spectra and thermogravimetric
properties. Their dyeing on, polyester, nylon and wool resulted in yellow,
orange and brown to red shades with good to excellent light fastness and
washing fastness properties.
Key Words: azo dyes, polyester, nylon, wool, fastness, properties
Iranian Polymer Journal / Volume 9 Number 2 (2000) ISSN: 1026-1265/2000
Derived from Two Heterocyclic Monomers
Ahmad Banihashemi* and S. Hassan Firoozifar
Department of Chemistry, Shiraz University, Shiraz, I.R. Iran
Received 26
June 1999; accepted 6 May 2020
ABSTRACT
New polyarylates were
synthesized by phase‑transfer catalyzed two‑phase polycondensation of
benzofuro[2,3‑b]benzofuran 2,9‑dicarbonyl chloride with bisphenols of various
derivatives and 2,13‑dihydroxy[7a,14c]dihydronaphtho-[2,1‑b]
naphtho[1´,2´:4,5]furo[3,2‑d] furan with various aromatic dicarboxylic acid
chlorides. All of these polyarylates dissolve readily in a wide range of organic
solvents such as N,N´-dimethylacetamide, N-N´-dimethylformamide,
and hexamethyl phosphoramide. These polyarylates have inherent viscosities of
0.14–0.30 dL/g and 10% weight loss between 302.9–455.8 ºC in
nitrogen atmosphere.
Key Words: polyarylates, polycondensation, benzofuro[2,3‑b]benzofuran-2,9‑dicarbonyl chloride, bisphenols, 2,13‑dihydroxy[7a,14c]dihydronaphtho[2,1‑b] naphtho[1´,2´:4,5]furo[3,2‑d] furan
Iranian Polymer Journal / Volume 9 Number 2 (2000) ISSN: 1026-1265/2000
Study of
Crystallinity of High-density Polyethylene by Inverse
Gas
Chromatography
Mousa Ghaemy*,
Mohammad Reza Hadjmohammadi and Reza Tabaraki
Department of
Chemistry, Faculty of Sciences, University of Mazandaran, Babolsar, I.R. Iran
Received 21 June 1998; accepted 14 February 2021
ABSTRACT
Method
of inverse gas chromatography (IGC) has been used for the physico-chemical
characterization of polymers for more than two decades. In this method the
polymeric stationary phase could be characterized by using probe molecules. The
retention volume of probe is a measure of the polymer-probe interaction and
show changes in the polymer structure at melting point or glass transition
temperature. Crystallinity of high-density polyethylenes (HDPE) of Poliran and
Irapol from Iranian petrochemical companies was studied. The effects of the
flow rates and the sample size on peak retention volume were investigated.
Modified techniques for measurement of flow rate and coating were used.
Retention diagram and degree of crystallinity were determined for a sample of
low-density polyethylene and the results were compared with those obtained for
HDPE. Experimental data of crystallinity and melting points showed that the
Iranian HDPE is a polymer with suitable engineering properties.
Key Words: high-density polyethylene (HDPE), crystallinity, inverse gas chromatography, retention diagram, soaking method
Iranian Polymer Journal / Volume 9 Number 2 (2000) ISSN: 1026-1265/2000
Continuous
Melt Impregnation Process: Materials Parameters
Zahed Ahmadi1, S. Reza
Ghaffarian1(*) and Davood Amiri2
(1) Polymer Engineering Department,
Amir Kabir University, Tehran, I.R. Iran
(2) Research Institute of Petroleum
Industry, Tehran, I.R. Iran
Received 4
December 1999; accepted 3 April 2020
ABSTRACT
The first step in the manufacturing of long and high fibre volume fraction of thermoplatic composite is the prepreg production with a melt impregnation process. During this process a polymeric matrix is introduced into the fibre tow. In this research an extruder equipped with a specially designed cross- head die was used for producing long and high fibre volume fraction of thermoplastic prepregs and to study the continuous melt impregnation of glass fibre roving with a polypropylene melt. A suitable relation determined from the cross-sectional area of the bundles and prepreg was selected as a proper indication of the impregnation quality. Our study shows that process and material parameters such as melt temperature and melt flow index have positive effect on the impregnation and those like line speed and melt pressure inside the cross-head die having a negative effect on fibre wetting.
Key Words: melt impregnation, prepreg, cross‑head die, polypropylene, fibre glass roving