the characterization of some methacrylate and acrylate homopolymers, copolymers and fibers via ...

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THE CHARACTERIZATION OF SOME METHACRYLATE AND ACRYLATE
HOMOPOLYMERS, COPOLYMERS AND FIBERS VIA DIRECT PYROLYSIS MASS
SPECTROSCOPY

A THESIS SUBMITTED TO
THE GRADUATE SCHOOL OF NATURAL AND APPLIED SCIENCES
OF
MIDDLE EAST TECHNICAL UNIVERSITY

BY

SURİYE ÖZLEM GÜNDOĞDU

IN PARTIAL FULFILLMENT OF THE REQUIREMENTS
FOR
THE DEGREE OF DOCTOR OF PHILOSOPHY
IN
POLYMER SCIENCE AND TECHNOLOGY

DECEMBER 2012
Approval of the thesis:

THE CHARACTERIZATION OF SOME METHACRYLATE AND ACRYLATE
HOMOPOLYMERS, COPOLYMERS AND FIBERS VIA DIRECT PYROLYSIS MASS
SPECTROSCOPY

submitted by SURİYE ÖZLEM GÜNDOĞDU in partial fulfillment of the requirements for
the degree of Doctor of Philosophy in Polymer Science and Technology
Department by,

Prof. Dr. Canan Özgen
Dean, Graduate School of Natural and Applied Sciences

Prof. Dr. Teoman Tinçer
Head of Department, Polymer Science and Technology

Prof. Dr. Jale Hacaloğlu
Supervisor, Chemistry Dept., METU

Examining Committee Members:

Prof. Dr. Nursel Dilsiz
Chemical Engineering Dept., Gazi University

Prof. Dr. Jale Hacaloğlu
Chemistry Dept., METU

Prof. Dr. Göknur Bayram
Chemical Engineering Dept., METU

Prof. Dr. Cevdet Kaynak
Metallurgical and Materials Engineering Dept., METU

Prof. Dr. Ahmet M. Önal
Chemistry Dept., METU

Date: 19.12.2012
ii
I hereby declare that all information in this document has been obtained
and presented in accordance with academic rules and ethical conduct. I
also declare that, as required by these rules and conduct, I have fully cited
and referenced all material and results that are not original to this work.

Name, Last Name : SURİYE ÖZLEM GÜNDOĞDU

Signature :

iii
ABSTRACT

THE CHARACTERIZATION OF SOME METHACRYLATE AND ACRYLATE
HOMOPOLYMERS, COPOLYMERS AND FIBERS VIA DIRECT PYROLYSIS MASS
SPECTROSCOPY

Özlem Gündoğdu, Suriye
Ph.D., Department of Polymer Science and Technology
Supervisor: Prof. Dr. Jale Hacaloğlu

December 2012, 177 pages

Poly(methyl methacrylate) possesses many desirable properties and is used in various
areas. However, the relatively low glass transition temperature limits its applications in
textile and optical-electronic industries. Monomers containing isobornyl, benzyl and
butyl groups as the side chain are chosen to copolymerize with MMA to increase Tg
and to obtain fibers with PMMA.

In this work, thermal degradation characteristics, degradation products and
mechanisms of methacrylate homopolymers, poly(methyl methacrylate), poly(butyl
methacrylate), poly(isobornyl methacrylate) and poly(benzyl methacrylate), acrylate
homopolymers, poly(n-butyl acrylate), poly(t-butyl acrylate), poly(isobornyl acrylate),
two, three and four component copolymers of MMA and fibers are analyzed via direct
pyrolysis mass spectrometry. The effects of substituents on the main and side chains,
the components present in the copolymers and fiber formation on thermal stability,
degradation characteristics and degradation mechanisms are investigated.

According to the results obtained, the depolymerization mechanism yielding mainly the
monomer is the main thermal decomposition route for the methacrylate polymers,
acrylate polymers degradation occurs by H-transfer reactions from the main chain to the
carbonyl groups. However, when the alkoxy group involves γ-H, then, H-transfer
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reactions from the alkoxy group to the CO group also takes place leading to a complex
thermal degradation mechanism.

The thermal degradation mechanisms and the relative yields of products are affected by
copolymerization due to the inter and intra-molecular interactions. As a consequence of
transesterification reactions new fragments can be generated.

In general, the samples taken from different parts of the fibers do not show different
thermal degradation behavior. However, upon fiber formation, enhancements in
intermolecular interactions decreasing the thermal stability and changing the product
distribution are detected.

Keywords: PMMA copolymers, fiber formation, thermal degradation, direct pyrolysis
mass spectrometry.

v
ÖZ

BAZI METAKRİLAT VE AKRİLAT HOMOPOLİMERLERİNİN, KOPOLİMERLERİN VE
FİBERLERİNİN DİREKT PİROLİZ KÜTLE SPEKTROMETRESİ İLE
KARAKTERİZASYONU

Özlem Gündoğdu, Suriye
Doktora, Polimer Bilimi ve Teknolojisi Bölümü
Tez Yöneticisi: Prof. Dr. Jale Hacaloğlu

Aralık 2012, 177 sayfa

Poli(metil metakrilat) fiziksel ve kimyasal özellikleri nedeniyle oldukça geniş uygulama
alanı olan bir polimer türü haline gelmiştir. Buna rağmen, oldukça düşük olan T ’si bu
g
polimerin tekstil ve optik-elektronik endüstrisinde kullanımını kısıtlamaktadır. Bu
nedenle, PMMA, T ’si arttırılmak amacıyla yan zincir olarak bütil, benzil ve izobornil
g
grupları içeren monomerlerle kopolimerleştirilmekte ve fiberleştirilmektedirler.

Bu çalışmada, metakrilat homopolimerler, poli(metil metakrilat), poli(bütil metakrilat),
poli(izobornil metakrilat), poli(benzil metakrilat) akrilat homopolimerler, poli(n-bütil
akrilat), poli(t-bütil akrilat), poli(izobornil akrilat), ve bu monomerlerin ikili, üçlü ve dörtlü
kopolimerlerinin, elyaflarının ısıl bozunum karakterleri, ürünleri ve mekanizmaları
doğrudan piroliz kütle spektrometresi yöntemi kullanılarak analiz edilmiştir. Bu
çalışmalar neticesinde, ana ve yan zincirlerdeki moleküllerin çeşitliliği, kopolimeri
oluşturan her bir parçanın birbiri üzerindeki etkisi ve elyaf oluşumunun ısıl kararlılık,
bozunum karakteristiği ve ısıl bozunum mekanizması üzerindeki etkisi incelenmiştir.

Elde edilen sonuçlara göre, metakrilat polimerleri için temel bozunum mekanizmasının
monomer oluşumuna neden olan depolimerizasyon olduğu görülmüştür, akrilat
polimerlerinin bozunumu ise ana zincirden karbonil gruba hidrojen transfer
reaksiyonuyla başlamaktadır. Fakat alkoksi grup γ-H içeriyorsa bu gruptan karbonil
gruba hidrojen transfer reaksiyonları da oluşabilmektedir ve bu tür durumlarda genellikle
reaksiyon, karmaşık termal bozunum mekanizmalarıyla devam etmektedir.
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Kopolimerleşme nedeniyle moleküller arası etkileşimin farklılaşmasının, maddelerin ısıl
bozunum mekanizmalarını ve ürünlerinin bağıl verimliliğini etkilediği gösterilmiştir.
Transesterifikasyon reaksiyonları sonucunda da yeni ürünler oluşmuştur.

Genel olarak, elyafların farklı bölgelerinden alınan örnekler farklı ısıl bozunum
davranışları sergilemezler. Fakat elyaf oluşumun etkisiyle moleküller arası etkileşimin
farklılaşması nedeniyle termal bozunum ürünlerinde ve bu ürünlerin ısıl kararlılıklarında
bazı değişikliklerin olabildiği gösterilmiştir.

Anahtar Kelimeler: PMMA kopolimerleri, elyaf oluşumu, ısıl bozunum, doğrudan piroliz
kütle spektrometresi.

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To my lovely husband, Gençay……..

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ACKNOWLEDGEMENTS

I would like to express my deepest gratitude to my thesis supervisor Prof. Dr. Jale
Hacaloğlu for her guidance, patience, understanding, kind support, encouraging
advices, criticism, and valuable discussions throughout my thesis. I thank Prof. Dr.
Ahmet M. Önal, Prof. Dr. Göknur Bayram, Prof. Dr. Cevdet Kaynak and Prof. Dr. Nursel
Dilsiz for their helpful comments and suggestions as committee members.

I would sincerely thank to Dr. Yusuf Nur for his guidance, patience and valuable
friendship during my learning stage of using the concerning laboratory instruments and
Dr. Evren Güler for her contribution in providing most of the polymers used in my
experiments.

My special thanks go to my mother, father and my brother for their continuous support,
patience and encouragement.

Last but not the least; I wish to express my sincere thanks to my husband Gençay
Gündoğdu for his support, understanding and endless love.

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TABLE OF CONTENTS
ABSTRACT ...................................................................................................................... iv
ÖZ ..................................................................................................................................... vi
ACKNOWLEDGEMENTS ................................................................................................ ix
TABLE OF CONTENTS .................................................................................................... x
LIST OF TABLES ............................................................................................................ xiii
LIST OF FIGURES .......................................................................................................... xv
LIST OF SCHEMES ....................................................................................................... xix
LIST OF ABBREVIATIONS ............................................................................................. ix

CHAPTERS
1. INTRODUCTION .......................................................................................................... 1
1.1 Polymers and Fibers ................................................................................................. 1
1.1.1 Fiber Spinning ................................................................................................... 2
1.1.1.1 Wet Spinning ............................................................................................. 3
1.1.1.2 Dry Spinning .............................................................................................. 4
1.1.1.3 Melt Spinning ............................................................................................. 4
1.1.1.4 Gel Spinning .............................................................................................. 5
1.1.2 Application Areas of Polymers .......................................................................... 5
1.2 Thermal Degradation of Polymers ............................................................................. 6
1.2.1 Depolymerization ........................................................................................... 7
1.2.2 Random Chain Scission ............................................................................... 7
1.2.3 Side Group Elimination ................................................................................. 7
1.3 Thermal Degradation Techniques ............................................................................. 7
1.3.1 Thermogravimetric Analysis (TGA) ................................................................... 8
1.3.2 Thermal Volatilization Analysis (TVA) ............................................................... 9
1.3.3 Differential Scanning Analysis (DSC) .............................................................. 10
1.3.4 Pyrolysis (Py) ................................................................................................... 11
1.3.4.1 Pyrolysis GC/MS (Py-GC/MS) ................................................................ 12
1.3.4.2 Direct Pyrolysis-MS (DP-MS) .................................................................. 13
1.4. Acrylate Polymers .................................................................................................. 15
x