Nanolif üretiminde çap kontrolü
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Dosyalar
Tarih
2013
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Namık Kemal Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Polimer solüsyon özellikleri ve elektro lif çekim sistemindeki üretim parametrelerinin nanolif çapına etki ettiği bilinmektedir. Nanolif çapı gelecek uygulamalarda oldukça önemli bir parametre olmasına rağmen, literatürde lif çapının kontrolüne yönelik yeterli sayıda çalışma bulunmamaktadır. Bu çalışmada elektrolif çekim yöntemi ile üretilen nanoliflere ait üretim ve çözelti parametrelerinin ortalama lif çapına etkileri incelenmiş, lif çapının kontrol edilmesinde belirgin etkisi olan parametreler belirlenmiştir. Yapılan çalışmalarda Polivinilalkol (PVA) ve Poliakrilonitril (PAN) polimerleri kullanılmıştır. PVA polimeri için çözücü olarak su kullanılmış, %10, %12 ve %14`lük konsantrasyonlarda 3 farklı çözelti hazırlanmıştır. Her çözelti için 2 farklı iğne çapı, 2 farklı besleme hızı ve 2 farklı mesafede, artan voltaj/mesafe oranlarında yüzey üretimi yapılmıştır. PVA polimerinden, farklı üretim parametrelerinde toplam 96 adet yüzey üretilmiştir. PAN polimeri için çözücü olarak Dimetilformamid (DMF) kullanılarak, %6, %8 ve %10`luk konsantrasyonlarda 3 farklı çözelti hazırlanmıştır. %6`lık ve %10`luk çözeltiler için, 2 farklı iğne çapı ve 2 farklı mesafede, artan voltaj/mesafe oranlarında nanolif üretimi yapılmıştır. %10`luk çözeltide ise lif eğrilmesi gerçekleşmemiştir. PAN polimerinden, farklı üretim parametrelerinde toplam 32 adet yüzey üretilmiştir. Hazırlanan çözeltilerin viskozite, iletkenlik ve pH değerleri ölçülmüştür. Çözeltilerden üretilen nanoliflerin görüntüsü Taramalı Elektron Mikroskobu (SEM) ile elde edilmiş, SEM görüntülerinden ortalama çap değeri belirlenmiştir. Ortalama çap değeri her bir numuneye ait SEM görüntüsünden 50 farklı ölçüm yapılarak belirlenmiş ve bu ölçümler sonucunda, her numuneye ait %CV değeri belirlenmiştir. Farklı konsantrasyonlarda ve farklı üretim parametrelerinde elde edilen nanoliflere ait ortalama lif çapları değerlendirildiğinde, konsantrasyonun, iğne çapının ve polimerin molekül ağırlığının ortalama lif çapını belirlemede önemli parametreler olduğu sonucuna varılmıştır. Hem PVA hem de PAN polimeri için, konsantrasyon artışının lif çapını belirgin şekilde arttırdığı görülmüştür. İğne iç çapının artması da, ortalama lif çaplarını her iki polimerde de arttırmıştır. Molekül ağırlığı daha büyük olan PAN ile üretilen nanoliflerde ortalama lif çaplarının PVA`ya göre daha yüksek olduğu görülmüş ve molekül ağırlığının artışının lif çapını arttırdığı belirlenmiştir. Uygulanan voltaj, besleme hızı ve mesafenin de ortalama lif çapına etkisi olduğu fakat bu etkilerin çoğu zaman belirsiz olduğu, lif çapı kontrolünde kullanılabilecek tutarlı sonuçlar vermediği kanısına varılmıştır.
As it is well known, polymer solution and production parameters in electro-spinning influence the nanofiber diameters. However there is no enough study in the literature for full control of fiber diameter in electro-spinning that is essential for future application. Therefore, this study aims to determine the most suitable parameters for a reliable control of fibre diameter. For this purpose, nanofibers were produced by using polyvinyl alcohol (PVA) and polyacrylonitrile (PAN) polymers. PVA polymers were solved with water to prepare three different solutions of 10%, 12% and 14% concentrations. For each solution fibre productions were carried out by increasing voltage/distance rates with two different needle diameters, feed rates and distances. Hence totally, 96 fiber samples were obtained from the PVA polymer based on different production parameters. Similarly, dimetylformamid (DMT) was used for PAN polymer as the solvent and three different solutions of 6%, 8% and 10% concentrations were prepared. For the 6% and 8% solutions, nanofiber productions were carried out by e increasing voltage/distance rates based on two different spine calibers and two different distances. In the 10 % concentrated solution fiber spinning didn?t occur. From PAN polymer thirty two nanofibre sample were produced in different parameters in total as fiber could not be obtained at 10% concentration. During production of nanofibers, viscosity, conductivity and pH values of the polymer solutions that were measured. After production of the samples, SEM images of the nanofibers were taken. The average fiber diameters and CV% values were determined from the SEM images by fifty measurements for each sample. The average fiber diameters of the nanofibers, which were produced in different concentrations and different production parameters, were evaluated. It was concluded that concentration, spine caliber and the molecular weight of the polymer are the most effective parameters on average fiber diameter in electro-spinning. It was seen that for both PAN and PVA polymer, the increase in the concentration clearly increases the fiber diameter. In addition, the increase in the inner diameter of the spine increased the average fiber diameters in both polymers. On the other hand, larger fibre diameters were observed in the PAN nanofibers which have more molecular weight compare to PVA polymer. Other parameters such as the voltage, the feed rate and the distance also have effect on the average fiber diameter, but most of the time these effects are unclear and don?t give consistent outcomes that can be used in the control of the fiber diameter.
As it is well known, polymer solution and production parameters in electro-spinning influence the nanofiber diameters. However there is no enough study in the literature for full control of fiber diameter in electro-spinning that is essential for future application. Therefore, this study aims to determine the most suitable parameters for a reliable control of fibre diameter. For this purpose, nanofibers were produced by using polyvinyl alcohol (PVA) and polyacrylonitrile (PAN) polymers. PVA polymers were solved with water to prepare three different solutions of 10%, 12% and 14% concentrations. For each solution fibre productions were carried out by increasing voltage/distance rates with two different needle diameters, feed rates and distances. Hence totally, 96 fiber samples were obtained from the PVA polymer based on different production parameters. Similarly, dimetylformamid (DMT) was used for PAN polymer as the solvent and three different solutions of 6%, 8% and 10% concentrations were prepared. For the 6% and 8% solutions, nanofiber productions were carried out by e increasing voltage/distance rates based on two different spine calibers and two different distances. In the 10 % concentrated solution fiber spinning didn?t occur. From PAN polymer thirty two nanofibre sample were produced in different parameters in total as fiber could not be obtained at 10% concentration. During production of nanofibers, viscosity, conductivity and pH values of the polymer solutions that were measured. After production of the samples, SEM images of the nanofibers were taken. The average fiber diameters and CV% values were determined from the SEM images by fifty measurements for each sample. The average fiber diameters of the nanofibers, which were produced in different concentrations and different production parameters, were evaluated. It was concluded that concentration, spine caliber and the molecular weight of the polymer are the most effective parameters on average fiber diameter in electro-spinning. It was seen that for both PAN and PVA polymer, the increase in the concentration clearly increases the fiber diameter. In addition, the increase in the inner diameter of the spine increased the average fiber diameters in both polymers. On the other hand, larger fibre diameters were observed in the PAN nanofibers which have more molecular weight compare to PVA polymer. Other parameters such as the voltage, the feed rate and the distance also have effect on the average fiber diameter, but most of the time these effects are unclear and don?t give consistent outcomes that can be used in the control of the fiber diameter.
Açıklama
Anahtar Kelimeler
elektrolif çekimi, nanolif çapı, PVA, PAN, çap kontrolü, electrospinning, nanofiber diameter, control of the diameter
