Hidrojen Transfer Kopolimerizasyonu İle Yeni Bir Poli(Ester-Amit) Sentezi ve Karakterizasyonu

Abstract

Günümüzde mevcut doğal ve sentetik polimerik biyomalzemelerin modifikasyonu ve yeni sentetik polimerik malzemelerin tasarımı çok ilgi çeken konulardır. Spesifik uygulamalar için istenilen mekanik özellikler ve biyolojik aktiviteye sahip polimerlerin gerekliliği ortaya çıkmıştır. Doğal polimerik biyomalzemelerin çeşitliliğindeki sınırlama ve kimyasal modifikasyonunun zorluğu araştırmacıları yeni sentetik polimerik malzemelerin tasarımına zorlamaktadır. Yeni alifatik poliesterler, polifosfoesterler, poliesteramitler, poliesterüretanlar, polianhidritler üzerinde en çok durulan sentetik polimer grupları olarak öne çıkmaktadır. Baz katalizli hidrojen transfer polimerizasyonu (HTP) ilk kez akrilamit monomerinden bir alifatik poliamit olan naylon-3 (poli-β-alanin) elde edilmesinde ortaya çıkarılmış özel bir anyonik katılma polimerizasyonu türüdür. HTP; akrilamit ve akrilik asit türevleri gibi vinil grubu ve asidik oynak proton içeren bir monomer ve nükleofilik bir başlatıcı varlığında gerçekleşmektedir. HTP ile bazı akrilamit, metakrilamit, akrilik asit ve metakrilik asit türevleri monomer olarak kullanılarak poliamitler, poliesterler ve poli(ester eter)’ler elde edilmiştir. Laktonların anyonik halka açılması polimerizasyonu ile karşılık gelen poliesterlerin sentezi ve biyomedikal uygulamaları literatürde yaygın olarak bilinen çalışmalardır. Biyomedikal uygulamalarda en yaygın kullanılan poliesterler ise poli(ε-kaprolakton) (PCL), poli(laktik asit) (PLA), poli(glikolik asit ) (PGA) ve poli(3-hidroksi bütirat) (P3HB)’tır. Tez çalışmasında, HTP ile polimerleşebilirliği en yüksek monomer olarak bilinen akrilamit ve komonomer olarak β-bütirolakton (P3HB’nin monomeri) farklı oranlarda (% mol; 10, 25, 50, 75 ve 90) kullanılarak farklı bileşimlerde yeni poli(ester amit)’ler sentezlenmiştir. İzole edilen kopolimerlerin bileşimi, ortalama mol kütleleri ve termal özellikleri sırasıyla elementel ve spektroskopik analizler (FTIR ve NMR), MALDI ve termal analiz (DSC ve TGA) ile aydınlatılmıştır. Spektroskopik yöntemlerden elde edilen sonuçlar değerlendirildiğinde besleme oranlarından farklı ama yakın bileşimlerde ürünlerin elde edildiği belirlenmiştir. Kopolimer bileşimini belirlemek için kullanılan NMR ve elementel analiz sonuçları birbiriyle tutarlıdır. Elde edilen kopolimerler içerisinde en yüksek 5000-6000 g/mol ortalama mol kütlesi değerine ulaşılmıştır. Kopolimerlerin DSC termogramlarında 0-10 oC arasında gözlenen camsı geçiş sıcaklığı kaymaları ana zincirlerde ester bloklarının varlığını kanıtlamaktadır. TGA termogramları ise yaklaşık 230 oC ve 330 oC merkezli iki basamaklı termal bozunma göstermektedir.,Nowadays, biologically and synthetically derived biodegradable biopolymers have attracted considerable attention. Diversity and complexity of in vivo environments cause the necessity of more specific biopolymers for these application. Similarly, for a specific application, necessity of polymers with desired biological activity and mechanical property have emerged. Limitation of diversity in the natural polymeric materials and difficulties in their chemical modification have forced investigators to begin designing of new synthetic polymeric materials. New aliphatic polyesters, polyphospoesters, polyesteramides, polyesterurethanes and polyanhidrides have come into prominence as the most elaborated synthetic polymer groups. Base-catalyzed hydrogen transfer polymerization (HTP) is a specific type of anionic addition polymerization developed to obtain naylon-3, which is an aliphatic polyamide, from acrylamide. HTP undergoes when one uses a monomer containing vinyl group and acidic (loose) proton (such as acrylamide and acrylic acid derivatives) and a nucleophilic initiator (also catalyst). HTP has been applied to some derivatives of acrylamide, methacrylamide, acrylic acid and methacrylic acid and yielded novel polyamides, polyesters and poly(ether ester)s. Synthesis of regarding polyester through anionic ring-opening polymerization of lactones and their biomedical applications are well-known studies in literature. Most common polyester used in biomedical applications are poly(ε-caprolactone) (PCL), poly(lactic acid) (PLA), poly(glycolic acid) (PGA) and poly(3-hydroxy butyrate) (P3HB). In the content of the thesis study, the highest polymerizability through HTP and the most frequently used monomer, acrylamide, and β-butyrolactone (monomer of P3HB) as a comonomer (% mole; 10, 25, 50, 75 ve 90) were used to synthesize a new poly(esteramide). Compositions, average molar masses and thermal properties of the isolated copolymers were elicited using by elemental and spectroscopic analyses (FTIR and NMR), mass spectrometry (MALDI)-MS and thermal analysis (DSC and TGA), respectively. The products (copolymers) were found to have compositions different from feed ratio but close when the results obtained from spectroscopic methods were evaluated of spectroscopic methods. The methods used to determime the copolymer composition were found to be consistent with each other. The highest average mass of 5000-6000 g/mol were reached for the copolymers prepared. Glass transition temperature shifts between 0 and 10 oC in the DSC thermograms of the copolymers proves the existence of ester blocks in the main chains. TGA thermograms exhibit two-step thermal decomposition shifts with centered at about 230 oC and 330oC.

Nowadays, biologically and synthetically derived biodegradable biopolymers have attracted considerable attention. Diversity and complexity of in vivo environments cause the necessity of more specific biopolymers for these application. Similarly, for a specific application, necessity of polymers with desired biological activity and mechanical property have emerged. Limitation of diversity in the natural polymeric materials and difficulties in their chemical modification have forced investigators to begin designing of new synthetic polymeric materials. New aliphatic polyesters, polyphospoesters, polyesteramides, polyesterurethanes and polyanhidrides have come into prominence as the most elaborated synthetic polymer groups. Base-catalyzed hydrogen transfer polymerization (HTP) is a specific type of anionic addition polymerization developed to obtain naylon-3, which is an aliphatic polyamide, from acrylamide. HTP undergoes when one uses a monomer containing vinyl group and acidic (loose) proton (such as acrylamide and acrylic acid derivatives) and a nucleophilic initiator (also catalyst). HTP has been applied to some derivatives of acrylamide, methacrylamide, acrylic acid and methacrylic acid and yielded novel polyamides, polyesters and poly(ether ester)s. Synthesis of regarding polyester through anionic ring-opening polymerization of lactones and their biomedical applications are well-known studies in literature. Most common polyester used in biomedical applications are poly(ε-caprolactone) (PCL), poly(lactic acid) (PLA), poly(glycolic acid) (PGA) and poly(3-hydroxy butyrate) (P3HB). In the content of the thesis study, the highest polymerizability through HTP and the most frequently used monomer, acrylamide, and β-butyrolactone (monomer of P3HB) as a comonomer (% mole; 10, 25, 50, 75 ve 90) were used to synthesize a new poly(esteramide). Compositions, average molar masses and thermal properties of the isolated copolymers were elicited using by elemental and spectroscopic analyses (FTIR and NMR), mass spectrometry (MALDI)-MS and thermal analysis (DSC and TGA), respectively. The products (copolymers) were found to have compositions different from feed ratio but close when the results obtained from spectroscopic methods were evaluated of spectroscopic methods. The methods used to determime the copolymer composition were found to be consistent with each other. The highest average mass of 5000-6000 g/mol were reached for the copolymers prepared. Glass transition temperature shifts between 0 and 10 oC in the DSC thermograms of the copolymers proves the existence of ester blocks in the main chains. TGA thermograms exhibit two-step thermal decomposition shifts with centered at about 230 oC and 330oC.