مطالعه خواص كششي نخ هاي بخيه توليد شده به روش الكتروريسي

چكيده انگليسي :

98 Study of Tensile Properties of Sutures Manufactured by Electrospinning Method Fatemeh Haghighat f haghighat@tx iut ac ir Date of Submission 2011 10 4 Department of Textile Engineering Isfahan University of Technology Isfahan84156 83111 Iran Degree M Sc Language Persian Supervisor S Abdolkarim Hosseini hoseinir@cc iut ac irAbstractUltrathin fibers with diameters ranging from submicron to several nanometers which are fabricated by anelectrospinning technique have received tremendous attention in biomedical fields in recent years In thepharmaceutical and medical fields for example this technique can be used to make wound dressings drugdelivery materials and tissue engineering scaffolds Producing the yarn from nanofibres is considered as oneof the great potentials in electrospinning These yarns can be used in various fields of medical applicationssuch as surgery sutures and drug delivery systems Both natural and synthetic materials have beeninvestigated for use as sutures in the past few years Amongst them biodegradable synthetic polymers offer anumber of advantages over more conventional materials for developing sutures In this research we carriedout electrospinning by using two differently charged nozzles to produce PLGA 10 90 nanofibers yarn PLGA nanofiber yarn has the potential to be applied in medical fields especially as absorbable suture Various electrospinning parameters such as solution applied voltage feed rate distance of two nozzles anddistance between nozzle and collected drum were optimized to produce good quality yarn Then mechanicalproperties of yarn such as straight and knot strength breaking elongation work of rupture and elasticmodulus were studied In order to improve the properties of this yarn heat setting process was done Toachieve these goals we developed the heat setting setup Two heat setting techniques using heat water anddry heat were tried and the influence of the heat setting process on the mechanical properties of yarn hasbeen studied Result has shown that heat setting with boiling water is better than other type of setting Thepresence of a knot lowered breaking load and rupture occurred consistently at the knot region Knot strengthof two type of surgery knot square and surgeon showed square knot strength is greater than other type ofknot In vitro study of degradation behavior of nanofiber yarn showed fast decrease in its mechanicalproperties that can be due to great surface area of nanofibers exposed to surrounding environment In the nextsection of research nanoindentation test conducted on nanofiber yarn and braid vicryl suture commercialsuture to compare behavior yarn associated with applied normal force The result indicated elastic recoveryof nanofiber yarn is less than braid suture No capillarity is desired in any case of suture application due tothe spread of microorganisms with the body fluid in between the fibers in multifilament sutures In nextapproach capillary rise in the nanofiber yarn and braid vicryl suture were studied The results demonstratednanofiber yarn has less capillarity than braid suture Finally Fracture morphology of nanofiber yarn hasinvestigated SEM images were used to analyze the broken ends of the yarns Observations showed fracturemorphology of yarn is very similar to stake and socket mechanism With analyze of fracture morphology ofsingle nanofiber mushroom ends were seen as normally associated with high speed breaking of ductilefilaments Keywords suture mechanical properties of nanofiber yarns PLGA setting process fracture morphology

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مطالعه خواص كششي نخ هاي بخيه توليد شده به روش الكتروريسي

PLGA , عمليات تثبيت , مورفولوژي پارگي