Bioactive polymer composites, composition

JL HE POLYMERIZATION OF VINYL MONOMERS in the void spaces of bulk wood results in wood—polymer composites of increased strength properties and dimensional stability see Chapter 6). Because the different environmental conditions expose in-service timber to attack by numerous wood-deteriorating microorganisms, it is desirable to enhance the biodegradation resistance of wood, with simultaneous improvements in mechanical behavior. This chapter summarizes the formation of bioactive wood-polymer composites (1-4). The basic approach is still in situ polymerization of vinyl monomers in wood, with the appropriate choice of a bioactive, toxic, functional group incorporated in the monomer, and with other modifications based on wood-polymer reactions. 

The impregnation of wood by polymers with TBT functional groups offers a viable route to the preparation of bioactive wood— polymer composites with a number of advantages. Polymer impregnation may be expected to improve the strength properties and dimensional stability of wood in water. The controlled release of the toxic TBT moiety, chemically linked to the polymer located within the wood, can increase the service life of wood while ensuring min-... 

Howdle SM, Watson MS, Whitaker MJ, Popov VK, Davies MC, Mandel FS, Wang JD, Shakesheff KM. Supercritical fluid mixing preparation of thermally sensitive polymer composite containing bioactive materials. J Chem Soc Chem Commun 2001 109-110. 

Zhitomirsky D et al (2009) Electrophoretic deposition of bioactive glass/polymer composite coatings with and without HA nanoparticle inclusions for biomedical applications. J Mater Process Technol 209(4) 1853... 

Knowles, J., Hastings, G., Ohta, H., Niwa, S., Boeree, N. Development of a degradable composite for orthopaedic use in vivo biomechanical and histological evaluation of two bioactive degradable composites based on the polyhydroxybutyrate polymer. Biomaterials 13, 491 96 (1992)... 

Aho, A. J., Tiiri, T., Kukkonen, J., Strandberg, N., Rich, J., Seppala, J. Yb-Urpo, A. (2004) Injectable bioactive glass/biodegtadable polymer composite for bone and cartilage reconstruction concept and experimental outcome with thermoplastic composites of poly(e-caprolactone-co-D,L-lactide) and bioactive glass S53P4. Journal of Materials Science Materials in Medicine, 15, 1165—73. 

Pielichowska K, Blazewicz S (2010) Bioactive polymer/hydroxyapatite (nano) composites for bone tissue regeneration. In Abe A, Dusek K, Kobayashi S (eds) Biopolymers. Springer, Berlin, pp 97-207... 

Bonfield, W. (1993). Design of bioactive ceramic-polymer composites. An Introduction to Bioceramics, pp. 299-303, Hench, L. L, and Wilson,]., eds., Singapore World Scientific. 

Parameters Affecting Self-Assembly and Functionalization When amphiphilic block copolymers are exposed to a solution that solvates only one of the blocks, the polymers self-assemble into micelles [126]. For applications in which bioactive polymers compose the micelle, particle size determines the maximum drug loading, blood-serum half-life, and bio distribution [127,128]. Block copolymer chain length and composition, as well as the method of self-assembly, were found to influence the final size of these particles [80, 129-131]. By varying these parameters, the size of the polymer aggregates could be controlled in the range from 30 nm to 1 pm [129,130]. 

The most important seaweed derived phenolic phytochemicals are phlorotannin polyphenols, which are uniquely found only in brown seaweeds [96], Phlorotannins are polymers which contain phloroglucinol as their monomeric component, and they are termed phlorotaimins since phloroglucinol is a common monomer unit [96]. As most tannins, similarly phlorotannins have the potential for cardiovascular disease management through an increase of HDL cholesterol and prevention of atherosclerosis [136-140], However, many recent reports have indicated more unique potential health benefits of phlorotaimins for a wide variety of diseases. A study by Li et al. [141] revealed that E. cava contains plenty of phlorotannin derivatives with interesting bioactivities. Chemical composition and antioxidant activity studies on E. cava showed that the major phlorotannins present are phloroglucinol, eckol. 

In microsphere sintering, pre-synthesized polymer microspheres or polymer/ceramic/bioactive addiction composites are sintered to produce a 3-D porous scaffold (56). Bioactive scaffolds can be fabricated through this technique, and they are demonstrated to be supportive to human osteoblast-like cells adhesion, growth, and mineralization (57). Scaffolds fabricated through this technique can have graded porosity structures. Mechanical properties close to cancellous bone also become possible when the microspheres are sintered into... 

Boccaccini, A. R. Maquet, V. Bioresorbable and bioactive polymer/bioglass (R) composites with tailored pore structure for tissue engineering applications. Cnmpno Terhrmi 63,2417-2429. 

Lu, H. H. EL-Amin, S. F. Scott, K. D. Laurencin, C. T. Three-dimensional, bioactive, biodegradable, polymer-bioactive glass composite... 

Howdle, S. M., Watson, M. S., Whitaker, M. J., Popwv, V. K, Davies, M. C., Mandel, F. S., Wang, J. D. Shakesheff, K. M. (2001). Supercritical fluid mixing preparation of thermally sensitive polymer composites containing bioactive materials. Chemical Communications Oiy. 109-110. 

Bioactive Polymer/Hydroxyapatite (Nano)composites for Bone Tissue Regeneration... 

However, HAp is difficult to shape in the complex forms required for bone treatment because of its hardness and brittleness. HAp powders, used for the treatment of bone defects, have the limitation that they easily migrate from the implanted sites. Therefore, novel composites of HAp and organic polymers that can compensate for the poor mechanical properties of HAp have become of great interest [45]. The concept of using bioactive HAp particles/modified polymer composites as implant materials for bone replacement was introduced by Bonfleld in the early 1980s [46]. Since then, HAp-modified polymer-based biocomposites have been widely studied for bone tissue replacement. They are described in detail in the forthcoming chapters of this review. 

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