Preparation of a porous scaffold based on polypropylene grafted with monomethylitaconate as potential bone graft
ABSTRACT Based on polypropylene (PP) grafted with different percentages of maleic anhydride (PP-g-MA) or monomethylitaconate (PP-g-MMI) a new porous scaffold was prepared with porosities in the range of 50–200 μm. The swelling capacity was analyzed, and
morphological, mechanical, and elemental analyses of these scaffolds were carried out. In vitro swelling in the simulated body fluid (SBF), chitosan (CHI) of low (70 kDa) and high (350 kDa) molecular weight, and chitosan-hydroxyapatite
solutions were assayed at 37 °C from 24 h to 4 weeks. The swelling degree (SD) of these scaffolds was in the range of 25%–125%.
The highest SD value was found in the low-molecular weight (LMW) chitosan solution. The PP-g-MMI and PP-g-MA with 0.7% and 1% of grafting, respectively, showed the highest SD values in the CHI solution. The in vitro treatment of the scaffold was performed by immersion in LMW chitosan and/or the double ionic diffusion (DID) method. The
pore structure of the scaffolds was unaltered after these treatments, as revealed by scanning electron microscopy (SEM). Mechanical
properties, that is, fracture resistance and deformation of the porous scaffolds depended on the percentage of grafting. Scaffolds
with a smaller pore size showed higher mechanical properties. Energy Dispersive Spectroscopy (EDS) measurements of PP-g-MMI with 0.7% of grafting after in vitro treatment revealed the formation of hydroxyapatite (HA) crystals with different morphologies on the porous scaffold. It was
concluded that the porous scaffold based on PP-g-MMI could be used as a potential prototype bone graft.
Keywordsporous scaffold–polypropylene–monomethylitaconate–maleic anhydride–hydroxyapatite
SourceAvailable from: M. Yazdani-Pedram[Show abstract] [Hide abstract]
ABSTRACT: To improve the compatibility and properties of blends based on high-density polyethylene (HDPE) and the ethylene-propylene copolymer (EPR), the functionalization of both through grafting with an itaconic acid derivative, monomethyl itaconate (MMI), was investigated. The grafting reaction was performed at 180degreesC in a Brabender Plasticorder using an initial monomer concentration of 3 phr in the case of HDPE and 5 phr in the case of EPR. 2,5-Dimethyl-2,5-bis(tert-butylperoxy)hexane was used as a radical initiator for the functionalization of HDPE and dicumyl peroxide was used as a radical initiator for the modification of EPR. The degree of grafting was 1.56% by weight for HDPE and 0.8% by weight for EPR. The effect of grafting on the processability, morphology, and thermal and mechanical properties of the blends are of particular interest. The results show that the grafting reaction increases the toughness and elongation at break of all tested blends and they retained their strength and stiffness. Moreover, the grafted polymers behaved as nucleating agents, accelerating the HDPE crystallization. These results are particularly relevant when both polymeric phases are modified. Morphological studies are in concordance with the mechanical characterization, showing a reduction of the rubber particle size and a better interfacial adhesion when both polymers are functionalized with MMI.Journal of Applied Polymer Science 08/2003; 89(8):2239-2248. DOI:10.1002/app.12454 · 1.64 Impact Factor
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ABSTRACT: This paper describes the development of medical applications for polyhydroxyalkanoates (PHAs), a class of natural polymers with a wide range of thermoplastic properties. Methods are described for preparing PHAs with high purity, modifying these materials to change their surface and degradation properties, and methods for fabricating them into different forms, including tissue engineering scaffolds. Preliminary reports characterizing their in vivo behavior are given, as well as methods for using the natural polymers in tissue engineering applications.International Journal of Biological Macromolecules 06/1999; 25(1-3):111-21. DOI:10.1016/S0141-8130(99)00022-7 · 3.10 Impact Factor
Annals of the New York Academy of Sciences 02/1988; 523:173-7. DOI:10.1111/j.1749-6632.1988.tb38510.x · 4.31 Impact Factor