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Supramolecular polyolefin thermoplastic elastomer blends and nanocomposite with shape-memory and self-healing effects

Title
Supramolecular polyolefin thermoplastic elastomer blends and nanocomposite with shape-memory and self-healing effects
Author
무하마드카쉬프
Advisor(s)
Prof. Young-Wook Chang
Issue Date
2016-02
Publisher
한양대학교
Degree
Doctor
Abstract
The aims of this research are to develop smart thermoplastic elastomers (TPEs) possessing shape memory and/or healing properties, and these aims were achieved by using supramolecular hydrogen bonding interactions. Supramolecular hydrogen bonded TPEs were prepared by crosslinking of semicrystalline maleated elastomers with 3-amino-1,2,4-triazole (ATA). The hybrid systems were developed by blending supramolecular TPE with different polymers and by incorporation of a nanofiller like modified graphene oxide. The supramolecular TPE and its blends with nylon 12 shows shape memory and healing effects under thermal stimulation, while the TPE/modified graphene oxide nanocomposites show the same effects under near infrared light stimulation. Triple-shape memory effects can be manifested in the two ATA-crosslinked semicrystalline maleated elastomers, and a blend of supramolecular elastomer with poly(ε-caprolactone). Chapter 1 gives an overview about different types of thermoplastic elastomers, shape memory polymers and supramolecular healable polymers. Section 3.1 discusses the crosslinking of maleated polyethylene-octene elastomer (mPOE) with different amounts of ATA to induce supramolecular hydrogen bonding networks. The amount of ATA added to the mPOE has a marked influence on the supramolecular hydrogen bonding networks. Fourier transform infrared (FTIR) analysis and X-ray photoelectron spectroscopy (XPS) was carried out to explain the interaction of mPOE with ATA. Thermomechanical properties, shape memory effect and thermal healing effects were examined to explain the interesting behavior of the elastomer. Section 3.2 explains melt blending of ATA crosslinked mPOE with nylon 12 in order to enhance its mechanical properties while still maintaining its thermal healing capability. Intermolecular interactions between ATA crosslinked mPOE and nylon 12 were investigated. Effects of nylon 12 content on the phase morphology, thermal properties, mechanical properties and scratch healing effects in the blends were studied. Section 3.3 focuses on the preparation of a supramolecular hydrogen-bonded polyolefin elastomer nanocomposites by melt blending of ATA crosslinked mPOE with octadecylamine modified graphene oxide (ODA-GO). Modification of graphene oxide with octadecylamine and its dispersion in the physically crosslinked elastomer was studied. Moreover, shape memory effect, locally triggering of shape recovery and healing properties of the nanocomposites was evaluated under near infrared (NIR) light exposure. The results revealed that ODA-GO acted as NIR-triggered nanoheaters as well as reinforcing filler for the elastomer matrix. Section 3.4 elucidates the preparation of triple-shape memory polymers (T-SMPs) by melt blending of ATA crosslinked semicrystalline maleated ethylene-propylene-diene terpolymer (A-EPDM) with semicrystalline thermoplastic poly(ε-caprolactone) (PCL). It was expected that PCL can have a certain degree of compatibility with A-EPDM via hydrogen bonding interactions. The effects of blend composition on morphology, thermomechanical properties and triple-shape memory properties of the A-EPDM/PCL blends were investigated. Section 3.5 explains the preparation of physically crosslinked elastomeric T-SMPs by melt blending of two semicrystalline maleated elastomers (maleated ethylene-propylene-diene rubber: mEPDM and maleated polyethylene-octene elastomer: mPOE) in the presence of a small amount of ATA. The blends have two well-separated crystalline melting temperatures within the crosslinked network. Dual-shape memory and triple-shape memory properties of the blends were studied using cyclic thermomechanical one-step and two-step programming, respectively. Chapter 4 concludes the results derived from the prepared composites, nanocomposites and blends. |본 연구에서는 분자사슬간 초분자수소결합에의한 네트워크를 형성시킨 폴리올레핀계 열가소성탄성체를 제조하였으며, 열적, 기계적특성, 형상기억특성 및 자가치유특성을 조사하였다. 초분자수소결합에 의한 네트워크 형성은 주쇄에 소량의 말레무수기를 갖는 결정성 폴리올레핀고무를 3-amino-1,2,4-triazole (ATA)과 용융블렌드 하여 ATA의 아민기와 말레무수기와의 반응에 의해 유도하였다. ATA로 가교된 폴리올레핀 고무는 결정상의 용융온도 이상으로 가열하여 변형시킨 후 냉각함으로써 원하는 임시 형태로 잘 고정되었으며, 결정용융온도 이상으로 가열시 재빨리 본래의 형상으로 회복되는 형상기억특성을 나타내었다. 또한, 시료 표면에 가해진 크랙은 결정상의 용융온도 이상으로 가열 시 수분내로 치유되어 본래의 기계적물성을 회복하는 자가치유특성을 나타내었으며, 이는 형상기억특성과 사슬간의 초분자적 수소결합에 기인한 것으로 생각되었다. ATA에 의해 초분자적 수소결합을 갖는 폴리올레핀고무에 소량의 나일론12를 용융혼합으로 첨가함으로써 형상기억특성 및 자가치유특성을 유지하며 기계적물성과 사용가능온도한계를 증가시킬 수 있었다. 이는 나일론 12의 아미드기가 수소결합에 의한 고분자간 상호작용으로 ATA 개질 폴리올레핀고무와 충분한 친화성을 갖기 때문으로 판단되었다. ATA로 개질시킨 폴리올레핀고무에 octadecyl amine으로 개질한 graphene oxide를 소량 첨가함으로써 기계적물성의 증가와 함께 가열 조건 뿐 아니라 근적외선 하에서 형상기억특성과 자가치유특성을 발현시킬 수 있었다. 이는 매트릭스 고분자에 분산된 그래펜 나노입자의 광열효과에 기인한 것으로 판단되었다. 물리적 가교결합을 가지며 서로 다른 온도 용융온도를 갖는 두 개의 결정상 도메인을 가짐으로써 3중 형상기억특성(triple shape memory effect)을 나타낼 수 있는 고분자 소재를 제조하였다. 이를 위하여 ATA로 개질시킨 결정성 폴리올레핀고무와 poly(ε-caprolacton) (PCL)과의 블렌드 및 말레무수기를 갖는 EPDM과 말레무수기를 갖는 POE를 ATA와 함께 용융 블렌드하는 방법을 이용하였다. 두 가지 블렌드 모두 초분자적 수소결합에 의해 물리적 가교구조가 형성되었으며, 하나의 네트워크에 용융온도가 40 oC이상 차이가 나는 두 개의 결정상 도메인이 존재함으로써 각각의 용융온도를 기준으로 가열냉각 시 원하는 형태로 고정되며, 각 도메인의 용융온도 이상으로 가열 시 단계별로 원래의 모양으로 회복될 수 있는 형상기억소재를 제조할 수 있었다.
The aims of this research are to develop smart thermoplastic elastomers (TPEs) possessing shape memory and/or healing properties, and these aims were achieved by using supramolecular hydrogen bonding interactions. Supramolecular hydrogen bonded TPEs were prepared by crosslinking of semicrystalline maleated elastomers with 3-amino-1,2,4-triazole (ATA). The hybrid systems were developed by blending supramolecular TPE with different polymers and by incorporation of a nanofiller like modified graphene oxide. The supramolecular TPE and its blends with nylon 12 shows shape memory and healing effects under thermal stimulation, while the TPE/modified graphene oxide nanocomposites show the same effects under near infrared light stimulation. Triple-shape memory effects can be manifested in the two ATA-crosslinked semicrystalline maleated elastomers, and a blend of supramolecular elastomer with poly(ε-caprolactone). Chapter 1 gives an overview about different types of thermoplastic elastomers, shape memory polymers and supramolecular healable polymers. Section 3.1 discusses the crosslinking of maleated polyethylene-octene elastomer (mPOE) with different amounts of ATA to induce supramolecular hydrogen bonding networks. The amount of ATA added to the mPOE has a marked influence on the supramolecular hydrogen bonding networks. Fourier transform infrared (FTIR) analysis and X-ray photoelectron spectroscopy (XPS) was carried out to explain the interaction of mPOE with ATA. Thermomechanical properties, shape memory effect and thermal healing effects were examined to explain the interesting behavior of the elastomer. Section 3.2 explains melt blending of ATA crosslinked mPOE with nylon 12 in order to enhance its mechanical properties while still maintaining its thermal healing capability. Intermolecular interactions between ATA crosslinked mPOE and nylon 12 were investigated. Effects of nylon 12 content on the phase morphology, thermal properties, mechanical properties and scratch healing effects in the blends were studied. Section 3.3 focuses on the preparation of a supramolecular hydrogen-bonded polyolefin elastomer nanocomposites by melt blending of ATA crosslinked mPOE with octadecylamine modified graphene oxide (ODA-GO). Modification of graphene oxide with octadecylamine and its dispersion in the physically crosslinked elastomer was studied. Moreover, shape memory effect, locally triggering of shape recovery and healing properties of the nanocomposites was evaluated under near infrared (NIR) light exposure. The results revealed that ODA-GO acted as NIR-triggered nanoheaters as well as reinforcing filler for the elastomer matrix. Section 3.4 elucidates the preparation of triple-shape memory polymers (T-SMPs) by melt blending of ATA crosslinked semicrystalline maleated ethylene-propylene-diene terpolymer (A-EPDM) with semicrystalline thermoplastic poly(ε-caprolactone) (PCL). It was expected that PCL can have a certain degree of compatibility with A-EPDM via hydrogen bonding interactions. The effects of blend composition on morphology, thermomechanical properties and triple-shape memory properties of the A-EPDM/PCL blends were investigated. Section 3.5 explains the preparation of physically crosslinked elastomeric T-SMPs by melt blending of two semicrystalline maleated elastomers (maleated ethylene-propylene-diene rubber: mEPDM and maleated polyethylene-octene elastomer: mPOE) in the presence of a small amount of ATA. The blends have two well-separated crystalline melting temperatures within the crosslinked network. Dual-shape memory and triple-shape memory properties of the blends were studied using cyclic thermomechanical one-step and two-step programming, respectively. Chapter 4 concludes the results derived from the prepared composites, nanocomposites and blends.
URI
http://dcollection.hanyang.ac.kr/jsp/common/DcLoOrgPer.jsp?sItemId=000000090334https://repository.hanyang.ac.kr/handle/20.500.11754/126771
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GRADUATE SCHOOL[S](대학원) > FUSION CHEMICAL ENGINEERING(융합화학공학과) > Theses (Ph.D.)
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