Development of compatibilizer using biomass-derived itaconic acid and packaging application

김정수 Graduate School, Yonsei University 2021 국내박사

본 논문에서는 최근 플라스틱 산업에서 이슈화 되고 있는 환경 문제를 고려 하여 바이오매스에서 유래된 이타콘산이라는 소재를 포장 분야에 적용하는 방 안을 연구하였다. 이타콘산은 셀룰로오스에서 얻을 수 있는 매우 중요한 유기 산 중 하나이며, 미국 에너지부에서 지정한, 주목해야할 바이오매스 기반 물질 12 개에 포함된다. 이 특별한 물질을 플라스틱 포장 산업에 응용하기 위하여, 범용적으로 널리 사용되고 시장규모가 증가하고 있는 폴리프로필렌 (PP) 산업 에 적용 가능한 기술을 고려하였다. 이에 따라, 이타콘산을 PP에 그라프트한 PP-g-IA 를 합성하는 방법을 고안하였는데, 이는 기존의 무수말레인산이 PP 에 그라프트 된 PP-g-MA와 유사한 기능적 구조를 가지고 있어 상용화제로 서의 효과를 기대할 수 있었다. PP-g-IA는 PP를 기반으로 한 블렌딩이나 복 합 소재에 사용할 수 있으며, 혼화성이 요구되는 대상 소재에 수소 결합과 물 리적 결합력이 증대될 수 있는 하이드록실기가 포함되어 효과가 극대화될 수 있다. 따라서 본 연구에서는 최근 재활용에 어려움이 있는 PP/EVOH 다층용 기에 응용 가능한 PP/EVOH 블렌딩에서의 PP-g-IA 상용화 효과를 비교하였 다.첫 번째 연구에서는, Brabender 장비를 이용하여 PP와 IA, 열개시제를 사용 하여 PP-g-IA를 제조하였으며, PP와 에틸렌 비닐 알코올 (EVOH)의 혼합물 에 적용하였다. 이타콘산의 투입량에 따라 PP에 그라프트 되는 비율을 조절하 고, 면밀한 구조분석을 통하여 PP-g-IA의 성공적인 합성을 확인하고, 합성의 최적 조건을 도출하였다. 이어서 두 번째 연구에서는 합성된 PP-g-IA를 응용하여 상용화제가 포함 된 PP/PP-g-IA/EVOH 블렌드와 상용화제가 미포함된 PP/EVOH 블렌드의 다양한 조성비에 따라, 형태학적, 열적, 유변학적 및 기계적 특성을 조사하였 다. PP-g-IA의 카르복실산 그룹과 EVOH의 하이드록실 그룹이 상용화 된 블 렌드에서 강력한 in situ 수소 결합을 형성하였고, 이는 PP/EVOH 블렌드의 형태학적 및 기계적 특성 향상에 기여하는 것을 확인하였다. 세 번째로, EVOH 내에서 에틸렌과 OH기의 조성비율이 변화함에 따라 투 입해야하는 상용화제의 적정 함량이 다를 것으로 예상되어, 에틸렌 함량이 각 각 다른 4종의 EVOH를 준비하고, PP/EVOH 블렌드를 제조하여 형태학적, 열적, 유변학적, 기계적 특성 등을 비교하였다. EVOH 종류에 상관없이 2.5phr 의 PP-g-IA가 적용된 모든 PP/EVOH 블렌드는 상용화제가 투입되지 않은 블렌드보다 영률, 인장 강도 및 파단 연신율에서 우수한 물성을 나타내었다. 네 번째로, 상업용 PP/EVOH/PP 다층용기 제조 시에 폐기되는 스크랩을 다 층용기의 PP층에 재활용하기 위하여 PP-g-IA를 적용하였다. 우선적으로 PP/scrap 블렌드를 제조하여 PP-g-IA의 적용 여부에 따라 상용화 효과를 비 교하였다. 이후에 상업용 PP/EVOH/PP 다층용기 내 PP층에 스크랩 5% 와 PP-g-IA를 함께 투입할 경우, 스크랩이 들어가지 않은 판매용 제품과 비교하 여도 색도와 단면, 이취 특성에서 양호한 결과를 나타냈으며, 불량률의 경우에 도 PP-g-IA가 미적용된 sheet에서 10% 이상의 불량률이 나타나는 것에 반에 PP-g-IA 처리구는 5% 이하의 불량률을 나타내는 것을 확인할 수 있었다.위 결과를 바탕으로, 새롭게 개발된 바이오매스 유래 상용화제인 PP-g-IA 는 PP/EVOH 블렌드 및 상업용 다층용기 재활용 연구에서 매트릭스 간 상용 성 향상에 효과적이고, 최적함량 사용 시 다양한 물성이 눈에 띄게 개선되는 것을 확인하였다. 향후, PP뿐만 아니라 PE나 기타 범용 플라스틱 패키징 고분 자에도 이타콘산을 그라프팅하여 새로운 상용화제를 제조할 수 있을 것이며, 다양한 복합재료에 응용하여 활용처를 넓힐 수 있을 것으로 기대된다. In this dissertation, we studied to apply biomass-derived itaconic acid to the packaging field in consideration of environmental issues. Itaconic acid (IA) is one of the most important organic acids which can be obtained from lignocellulose, and is included in the top 12 building block chemicals of the U.S. Department of Energy. We wanted to apply this special material to the PP industry, which is the most widely used in the plastic packaging industry. Itaconic acid, a material derived from biomass, was grafted onto polypropylene to synthesize PP-g-IA as a compatibilizer. This has a functional structure similar to that of conventional maleic anhydride grafted PP-g-MA, so the compatibilizing effect was expected. PP-g-IA can be used in blending and composite materials based on PP, and the effect is maximized if the target material requiring miscibility includes a hydroxyl group capable of hydrogen bonding. Accordingly, the compatibilizing effect between PP/EVOH and PP/CF was confirmed in this study. First, we used polypropylene grafted with itaconic acid (PP-g-IA) as a compatibilizer to prevent phase separation phenomenon which occurs upon blending polypropylene (PP) and ethylene-vinyl alcohol copolymer (EVOH). A compatibilizer was prepared using graft copolymerization of itaconic acid (IA) onto PP where input ratio of IA was 1, 2, 5, and 10 wt.%. To confirm the structure of PP-g-IA and the graft ratio of IA onto PP, we used 1H NMR and FT-IR. We tested the compatibilizer which has highest graft ratio of 1% in immiscible PP/EVOH blends. The morphologies of PP/PP-g-IA/EVOH blends were analyzed by SEM. Thermal and mechanical properties of the blends were analyzed by DSC and UTM. PP-g-IA enhanced the interfacial adhesion of PP and EVOH copolymer. Second, we prepared blends of polypropylene (PP) and ethylene vinyl alcohol (EVOH) with and without a PP-g-IA. We investigated the morphological, thermal, rheological, and mechanical properties of a compatibilized blends (PP/EVOH/PP-g-IA) and not compatibilized blends (PP/EVOH). Our experiments show that the carboxylic acid group of PP-g-IA and the hydroxyl group of EVOH form strong in situ hydrogen bonds in the compatibilized blend, so that the morphological and mechanical properties of the compatibilized blend are better than those of the non-compatibilized blend. showed results. Third, The PP/EVOH blends were prepared by varying the ethylene content of EVOH and adding a PP-g-IA. We investigated the morphological, thermal, rheological, tensile, and barrier properties of the PP/EVOH blends. The compatibilized PP/EVOH blends with 2.5phr of PP-g-IA have higher Young’s moduli, tensile strength, and greater elongation at break than those of non-compatibilized blends. Barrier properties also improved with the addition of compatibilizer in the L and F types. Fourth, PP-g-IA was applied to the PP layer in the multi-layer container to recycle scrap discarded during the manufacture of commercial PP/EVOH/PP multi-layer containers. PP/scrap blends with or without PP-g-IA were prepared and the compatibility effect was compared. After that, when 5% of scrap and PP-g-IA are added to the PP layer in a commercial PP/EVOH/PP multi-layer container, good results are obtained in color, cross-section, and odor characteristics compared to commercial products that do not contain scrap. In the case of defective rate, it was confirmed that the defective rate of PP-g-IA treated group was less than 5%, whereas the defective rate of 10% or more appeared in the sheet to which PP-g-IA was not applied. Based on the above results, it was confirmed that the newly developed biomass-based PP-g-IA improves the compatibility between the PP and EVOH. Also, in the multi-layer container recycling study, it was confirmed that scrap can be recycled to the PP layer. In the future, it is expected that a new compatibilizer can be prepared by grafting itaconic acid not only on PP but also on PE or other general plastic packaging polymers, and it is expected to be applied to various composite study.

고분자 상용화제를 포함하는 폴리케톤/폴리카보네이트 블렌드의 형태학과 기계적 물성

서동찬 서울대학교 대학원 2020 국내박사

반결정성 고분자인 폴리케톤 (polyketone, PK)은 에틸렌, 프로필렌, 일산화탄소의 공중합 반응으로 만들어지며, 높은 인장강도와 우수한 내화학성, 내투과성, 내마모성 등의 특성을 갖기 때문에 차세대 엔지니어링 플라스틱으로서 주목받고 있는 소재이다. 하지만 대다수의 반결정성 고분자들에서 나타나는 노치 존재하에 취성파괴의 특성 때문에 낮은 충격강도를 나타낸다. 따라서 넓은 분야에서 상업적으로 이용되기 위해서는 내충격성의 향상이 필수적으로 요구된다. 본 연구에서는 내충격성을 향상시키는 가장 일반적인 방법인 고무에 의한 강인화 가 아닌 열가소성고분자인 폴리카보네이트 (polycarbonate, PC)를 이용한 강인화 를 통해 탄성률 및 강성의 손실 없이 충경강도를 향상시키고자 하였다. PK/PC 블렌드는 비상용성을 나타내기 때문에, 적절한 상용화제를 도입하여 기계적 물성과 충격강도를 향상시키고자 하였다. 이 때에 도입하는 상용화제에 의해 각 상의 계면장력이 어떻게 변화하며, 이 것이 블렌드의 형태학, 기계적 물성 및 내충격성에 어떻게 영향을 미치는지 규명하고자 하였다. 첫 번째로는 화학적 상용화 방법을 이용하여 PK/PC 블렌드의 내충격성을 향상시키고자 하였다. 폴리아미드6 (polyamide6, PA6)와 스티렌-부틸렌-스티렌 공중합체 (poly[styrene-b-(ethylene-co-butylene)-b-styrene], SEBS) 및 무수 말레인산 (maleic anhydride, MA)으로 개질된 SEBS (SEBS-g-MA)를 상용화제로 도입하는데, SEBS와 SEBS-g-MA의 조성에 의한 블렌드의 형태학과 배열 형태의 변화를 이론적으로 분석하고 실험적으로 입증하였다. 상용화제의 조성에 따라 삼성분계 블렌드 내 각 상의 배열 형태가 다양하게 나타났으며, 이러한 형태학의 차이가 블렌드의 기계적 물성 및 강인성에 영향을 미치는 것으로 나타났다. 또한 블렌드의 각 상의 배열 형태가 강인화 메커니즘에 미치는 영향을 분석하기 위해 파괴거동을 관찰하였다. 두 번째는 비반응성 상용화제를 도입하여 PK/PC 블렌드의 기계적 물성 및 강인성을 향상시키고자 하였다. 화학적 반응이 아닌 물리적 상용화 방법을 도입하기 위해 적절한 상용화제가 요구되었고, 이를 위해 삼성분계 블렌드의 배열형태를 이론적으로 예측하였다. PA6를 물리적 상용화제로 선정하였으며, PA6 도입에 의해 계면접착력 향상으로 PC 입자가 완전히 캡슐화된 형태학이 나타났다. 또한 기계적 물성과 충격강도의 향상이 동반되었다. 추가적으로, PA6의 구조가 일부 변경됨에 따라 블렌드의 형태학 및 기계적 물성에 미치는 영향을 파악하기 위해 각각 폴리아미드612 (polyamide 612, PA612) 와 폴리아미드12 (polyamide 12, PA12)를 상용화제를 도입하였다. PA12에 의해서는 PK/PC 블렌드의 상용성이 개선되지 않았으며, PA612에 의해서는 상용성이 향상되었다. 같은 상용화제 함량에서 PC 입자크기는 PA6를 도입한 경우가 PA612를 도입한 경우보다 작았지만, 충격강도의 경향은 다르게 나타났다. 충격강도와 파괴거동 관찰을 통해 PK/PC 블렌드에서 입자크기가 강인화에 미치는 영향을 규명하였다. Semi-crystalline polymer polyketone (PK) is made by copolymerization of ethylene, propylene and carbon monoxide. PK is attracting attention as engineering plastic because of its high tensile strength, excellent chemical resistance, permeability, and abrasion resistance. However, PK has low impact strength because of its brittle fracture characteristics. In order to be used commercially in a wide field, it is necessary to enhance the impact strength. The most common method of enhancing impact resistance is toughening by blending with rubber, which leads to a loss of modulus. Therefore, in this study, we tried to improve the impact strength without reducing the modulus by toughening using polycarbonate (PC), a thermoplastic polymer. Since PK/PC blends exhibit incompatibilities, an appropriate compatibilizer is introduced to enhance mechanical properties and impact strength. The purpose of this study was to investigate how the interfacial tension changes with the introduction of compatibilizer, and how it affects the morphology, mechanical properties and impact resistance of the blend. First, polyamide 6 (PA6) and styrene-butylene-styrene copolymer (SEBS) and SEBS-g-maleic anhydride (SEBS-g-MA) was introduced as a chemical compatibilizer. The morphological difference of the blends by changing the ratio of SEBS and SEBS-g-MA was theoretically predicted and experimentally verified. Depending on the composition of the compatibilizer, the arrangement of each phase in the blends was varied, and this morphological difference was found to affect the mechanical properties and toughness of the blend. We also observed the failure behavior to analyze the effect of the morphology of the blend on the toughening mechanism. Secondly, non-reactive compatibilizers were introduced to enhance the mechanical properties and toughness of PK/PC blends. Appropriate compatibilizer was required to introduce the physical compatibilization, and he arrangement of the ternary blend was predicted theoretically. PA6 was selected as a physical compatibilizer, and the introduction of PA6 resulted in improved interfacial adhesion. It was aaccompanied by an increase in mechanical properties and impact strength. In addition, compatibilizers were introduced for polyamide 612 (PA612) and polyamide 12 (PA12) to investigate the effect of compatibilizer structural differences on the morphology and mechanical properties of the blends. The compatibility of PK/PC blends was not improved with PA12, and the compatibility was improved with PA612. At the same compatibilizer content, PC particle size was smaller than that of PA612 when PA6 was introduced, but the impact strength tended to be different. The effect of particle size on toughening in PK/PC blends was investigated by measuring impact strength and observing failure behavior.

상용화제 효과를 이용한 PPS/PET blends 물성평가 연구

홍지현 서강대학교 일반 대학원 2009 국내석사

The PPS/PET blending of polymers provides a powerful route for obtaining materials with improved property/cost performances. Since most blended polymers are immiscible, compatibilization is required to obtain maximum synergy. Several excellent reviews on the compatibilization of polymer blends exist. However, our approach is to present all known compatibilization techniques as a kind of toolbox for blend compatibilization. In this study, PPS (Polyphenylene Sulfide) and PET (Polyethylene terephthalate) blends and SEBS,m-PS were used as compatibilizer for the blends of polyphenylene sulfide / Polyethylene terephthalate. In PPS/PET blends having compatibilizer SEBS, m-PS which was confirmed that the elastomers were dispersed finely because of high compatibility with the PPS/PET matrix, the toughness was improved efficiently by the conventional compatibilizer, which the diameter of dispersed compatibilizer particles was larger, and the particles were deformed high content of compatibilizer. These finely particles were fractured easily, and many cracks, which were distributed. The purpose of this study is to examine the effect of compatibility between PPS/PET as a matrix polymer compatibilizers as elastomers on the improvement of toughness of the blends. Thermal properties of composites are performed on DSC. And the mechanical properties, including impact strength and tensile properties and morphology of blends, were investigated by UTM, DMA and scanning electron microscopy.

Morphological, mechanical and optical properties of polymer blend film containing poly(ethylene terephthalate) with compatibilizers

한권형 Greduate School, Korea University 2021 국내박사

In this paper, the optical properties of poly(ethylene terephthalate) (PET) film were studied by blending PET with various engineering resins and compatibilizers and then stretching them to improve the reflectivity of the PET film First, syndiotactic polystyrene (s-PS) polymer and various compatibilizers were blended into the PET polymer, and the best compatibility was found when 5phr of PS-g-oxazoline (PS-g-OXA) compatibilizer was added, and then this blend was stretched. As a result of the evaluation of the optical properties, the compatibility of blending was excellent, but it did not show good results in improving the reflectivity. The reason for this is that the interfacial adhesion between PET and s-PS is dominant over the stress in the process of stretching the film. Secondly, poly(phenylene ether) (PPE) polymer was blended into PET one, along with various compatibilizers. Among the various compatibilizers, PS-g-OXA showed the best compatibility, and films after stretching confirmed it to have good reflectivity through optical property evaluation. If the previous two experiments studied optical properties by applying compatibility through compatibilizers to the PET film, the third experiment blended various polymer with in PET films to ensure mass production stability along with the improvement of reflectivity. Among the various polymers, cyclic olefin copolymer (COC) and poly olefin elastomer (POE) was shown to have excellent thermal and surface properties, so those polymers was blended with PET and high-density polyethylene-g-maleic anhydride (HDPE-g-MAH). After making the films through the stretching, optical properties evaluated.

IPN's of Polyurethane/Natural Rubber with Reactive Compatibilizer

金春東 전남대학교 1997 국내석사

폴리우레탄(PU)과 천연고무(NR)를 조성고분자로 하고 상호침투하는 고분자 구조(Interpenetrating Polymer Network : IPN)를 제조함에 있어서, 조성고분자간 상호작용하는 반응성 상용화제를 도입하였으며, 이의 함량과 PU/NR의 조성비를 변화시켜 PU/NR IPN을 동시중합법으로 합성하였다. 조성고분자간 상호작용하는 반응성 상용화제로 maleic anhydride(MAH)를 선택하였고, PU 조성과는 maleimide-terminated urethane을 형성하게 하고 NR과는 그라프트 반응을 유도하였으며, 반응성 상용화제인 MAH와 각각의 조성 고분자와의 반응을 FT-IR로 확인 하였다. 톨루엔 내에서 Benzoyl Peroxide(BPO)를 개시제로 사용하여 천연 고무에 MAH를 그라프트시킨 maleic anhydride grafted natural rubber(NR-g-MAH)를 용액 그라프트법(solution grafting method)으로 제조하였고, 이를 NR 조성에 포함시켜 반응성 상용화제의 함량을 변화시켰다. PU/NR IPN은 NR과 NR-g-MAH를 톨루엔에 완전히 용해시키고, 천연고무의 가교제인 divinyl benzene(DVB)과 개시제인 BPO를 투입한 후 균일하게 교반하였고, 천연고무 조성물의 혼합액에 일정한 조성비에 따라 폴리우레탄의 조성물인 polytetramethylene ether glycol(PTMEG)과 4,4'-diphenylmethane diisocyanate(MDI) 그리고 가교제인 trimethylolpropane(TMP)을 차례로 투입한 다음 동시중합법으로 적정 시간 동안 반응시키고, Petri-dish에 부은 후 내부의 반응물을 80℃ 오븐에서 24시간 동안 완전히 반응시킨 후 80℃ 진공 오븐에서 용매를 완전히 제거하여 합성하였다. IPN 합성시의 제반 변수가 조성 고분자간 상호침투도 및 최종 생성물의 물성에 미치는 영향을 비교·검토하기 위하여 밀도, 경도, 용매에서의 팽윤비, 기계적 성질, 동적 기계적 성질 등을 조사하였다. PU와 NR의 함량이 동일하고 반응성 상용화제의 함량을 달리하여 제조한 IPN은 MAH의 함량이 증가함에 따라 조성간 반응이 증가하여 인장강도 등의 기계적 성질과 DMA에 의하여 측정된 동적 기계적 성질, elastic modulus가 향상되었다. 또한, 조성간 상호침투도가 증가하여 밀도와 경도가 증가하였으며, PU와 NR간 상용성이 향상되어 용매에 대한 팽윤도가 감소하였다. PU와 NR의 조성비를 변화시켜 제조한 IPN은 MAH를 첨가하지 않은 경우, 각각의 조성고분자의 함량에 비례하는 물성거동을 나타내었으며, 상용화제를 첨가하여 제조한 IPN은 모든 조성에서 보다 향상된 물성 거동을 보였다. 본 연구의 결과 PU와 NR의 두 조성에 조성간 상호 반응하는 상용화제를 첨가함으로써 조성간 상분리가 억제되어 상호침투도가 증가하였으며, 이로 인해 상용성이 향상되어 전체적인 물성이 향상됨을 알 수 있었다. 또한, 각각의 결과로부터 구조-물성거동 간에 서로 밀접한 상관관계가 있음을 알 수 있었다. Interpenetrating polymer networks(IPN's) of polyurethane(PU) and natural rubber(NR) with different composition of PU and NR, amount of reactive compatibilizer, were synthesized through simultaneous solution polymerization. Maleic anhydride(MAH) was selected as a reactive compatibilizer between PU and NR, the each reactions between reactive compatibilizer and NR, ending isocyanate groups in MDI were confirmed with FT-IR. Maleic anhydride grafted natural rubber(NR-g-MAH) was synthesized with benzoyl peroxide(BPO) in toluene at 80℃. And NR-g-MAH was included in NR composition. PU/NR IPN's were synthesized as fllow. NR and NR-g-MAH were dissolved throughly in toluene. When the dissolution was completed, divinyl benzene(DVB) as the for crosslinking agent as well as BPO was added. After uniform stirring, polytetramethylene ether glycol(PTMEG), 4,4'-diphenylmethane diisocyanate(MDI), and trimethylolpropane(TMP) were added in NR solution. After proper reaction, the mixture was poured into petri-dish and reacted in a drying oven at 80℃ for 24hrs. Finally, the product was dried in a vacuum oven at 80℃ for another 24hrs. Density, hardness, swelling ability on toluene, mechanical property and dynamic mechanical property of the final products were investigated and analyzed to evaluate the effect of PU/NR composition and reactive compatibilizer. For PU/NR IPN's with different amount of MAH; the properties of density, hardness were improved and swelling ratio was lowered with increasing the reactive compatibilizer. Mechanical property, dynamic mechanical property, and elastic modulus were also improved. For the PU/NR IPN's with different PU/NR composition, the properties were proportion to the each composition ratio. From the above results, the general properties of PU/NR IPN were improved, because of the improved compatibility triggered by inhanced interpenetration due to reactive compatibilizer.

Polyetherketoneketone/Graphene Nanoplatelet Composites via Non-covalent Functionalization Using Amphiphilic Block Copolymer for Improved Dispersion

Juyeon Lee 고려대학교 대학원 2024 국내석사

As the demand to replace metals used in aerospace equipment and transportation devices for fuel efficiency increases, lightweight plastics are becoming more important materials. Among the materials, bearings parts used in aerospace equipment and transportation device must have excellent heat resistance. They must withstand temperatures exceeding 200 °C due to frictional heat generated during operation. Additionally, they must satisfy mechanical properties similar to metals. To fulfill these requirements, super engineering plastics must be applied. Among the suitable super engineering plastics, poly etherketoneketone (PEKK) is most suitable material. However, to be applied in the industry, durable performance, including strength and dimensional stability, needs improvement. One facility method to achieve the improvement is applying polymer composites. Polymer composites are materials created by mixing two or more kind of materials. Among the materials, graphene nanoplatelets (GNPs) are lighter than other materials like glass fiber and having superior mechanical properties. However, there are issue regarding GNP aggregation. Poor dispersion of fillers within the composite leads to irregularity in composite properties and degradation. To effectively enhance performance of polymer composites, the issue of filler dispersion needs to be solved. To improve GNPs dispersion, functionalization GNPs was chosen as the method. Polymer compatibilizer will be applied via noncovalent functionalization. Block copolymer, pyrene-functionalized PMMA-b-PDMAEMA (PIB) was synthesized for use as a compatibilizer. We measured the molecular weight of the synthesized compatibilizer by GPC and the structure of compatibilizer were analyzed through 1H-NMR and FT-IR. The functionalized GNP was analyzed through Raman, TGA, AFM and SEM. Optical properties of neat PEKK, P-GNP/PEKK and F-GNP/PEKK composites were confirmed through SEM. Also, neat PEKK, P-GNP/PEKK and F-GNP/PEKK composites was analyzed for crystallinity using DSC and XRD. Mechanical properties were analyzed by UTM, and thermal properties were analyzed using DMA and TMA. Through these analyzes, the application of compatibilizer effectively improves GNP dispersion in the composite. Furthermore, improvements were confirmed in the mechanical and thermal properties. According to the improvements, it is inferred that F-GNP/PEKK composites has the excellent durability. Therefore, using PEKK composites reinforced with functionalized GNP, weight reduction will be effectively achieved in the transportation field. 항공우주장비와 운송 기기의 연료 절감을 위해 기기에 사용되는 금속을 대체하고자 하는 사회적 요구가 증가하며, 무게가 가벼운 플라스틱이 각광받고 있다. 그 중에서 항공우주장비와 운송 기기의 부품으로 사용되는 베어링은 뛰어난 내열성을 가져야 한다. 주행 중 발생하는 마찰열에 의해 브레이크 오일의 온도가 200 °C를 넘기므로 고온에서 물성 변화가 없어야 한다. 그리고 금속과 유사한 기계적 성질을 만족해야 하기 때문에 슈퍼 엔지니어링 플라스틱을 적용하여야 한다. 그 중 가장 적합한 소재로 poly(etherketoneketone) (PEKK) 가 있다. 하지만 PEKK가 산업에 적용되기 위해서는 강도, 치수안정성을 포함한 내구성이 향상되어야 한다. 그 중 가장 많이 사용되는 방법은 고분자 복합재료의 도입이다. 고분자 복합재료는 두가지 이상의 고분자 물질이나 고분자 물질이 아닌 재료를 섞어서 만든 재료이다. 그 중에서 graphene nanoplatelet (GNP)은 유리섬유와 같은 재료보다 가벼우며 기계적 특성이 뛰어나 연구의 필요성이 높아지고 있다. 그러나 GNP끼리 응집하는 문제가 있으며 복합재료 내 필러의 낮은 분산성은 복합체 특성의 불규칙성을 야기하고 물성을 저하한다. 고분자 복합재료의 효과적인 특성 향상을 위하여 필러의 분산성이 향상되어야 한다. 본 연구에서는 이러한 이슈를 해결하기 위해 GNP 표면에 고분자 형태의 상용화제를 사용하여 기능화 하고자 하였으며 이러한 상용화제가 기계적, 열, 모폴로지 특성에 미치는 영향에 대하여 연구하였다. Pyrene-functionalized PMMA-b-PDMAEMA (PIB)을 상용화제로 사용하기 위한 고분자 블록공중합체의 합성을 진행하였다. 이를 GNP의 표면에 비공유전자결합으로 관능화하였다. 합성한 고분자 상용화제에 대하여 GPC을 통해 분자량을 측정하였고 1H-NMR, FT-IR을 통해 구조적 분석을 진행하였다. 관능화된 GNP는 Raman, TGA를 통해 분석하였으며 관능화된 GNP를 적용한 PEKK 복합재료를 DSC, XRD를 통해 결정화도 및 결정화 거동을 분석하였다. UTM을 통한 기계적 특성을 구하였으며 DMA, TMA를 통한 열적 특성을 분석하였다. 관능화된 GNP와 복합 재료에 대한 광학적인 특성은 FE-SEM을 이용하여 확인하였다. 이러한 분석을 통해 PIB 상용화제 적용은 복합재료 내의 GNP 분산성을 효과적으로 향상시키는 것을 확인할 수 있었고, 내구성에 영향을 미치는 기계적, 열적 특성이 향상되었음을 확인하였다. 이렇게 제조된 PEKK 복합재료를 재료로 하여 항공우주장비, 운송 기기의 부품을 만들 때 무게가 효과적으로 감소될것으로 사료된다.

상용화제를 이용한 PET/PP 블렌드 섬유의 제조 및 Curl 형성 거동

박용완 전북대학교 일반대학원 2014 국내박사

고분자 복합 소재 및 bilayer 이종접합 복합 소재에서의 계면상용성

이하영 수원대학교 2024 국내석사

In this study, the modification of kaolin, both chemically and mechanically, significantly enhanced the compatibility of PLA/PVB blends. This enhancement led to polymer composites with enhanced tensile strength, Young’s modulus, elongation at break, and toughness. Notably, the use of HNO3 yielded the most pronounced compatibilizing effect. Furthermore, kaolin subjected to both acid and calcination treatments exhibited higher effectiveness than that treated with acid alone. However, kaolin treated with H2SO4 showed a reduction in these properties owing to chain scission caused by the acid. In addressing the thermal and impact resistance limitations of PLA, the incorporation of mica into PLA and PLA/PVB was explored. Despite its low compatibility of mica and PLA, subsequent integration with PVB revealed significant improvements. Specifically, mica particles, particularly those less than 100 µm and greater than 500 µm in size with high density, were found to enhance these properties. Thus, the incorporation of mica, alongside PVB, can improve the compatibility between PLA and PVB. The study further investigated the enhancement of compatibility in PBT/PEG (15 wt%) blends through the addition of two compatibilizers, PAn and PAc. These agents facilitated improved interfacial interactions, stabilizing the blend’s properties. The incorporation of 2.0 phr of either PAn or PAc enhanced their compatibility, thereby increasing their mechanical properties and viscosity. This miscibility improved with increasing compatibilizer concentrations but plateaued at a saturation point, beyond which the compatibilizer functioned as a plasticizer, diminishing mechanical and thermal properties. These findings underscore the potential of PAn and PAc as effective compatibilizers in PBT/PEG blends, especially for applications demanding enhanced mechanical performance. Additionally, the impact of surface treatment on the compatibility between SUS and PA 6,6 was examined. Surface treatment, which increased SUS’s surface roughness, was found to enhance the mechanical properties. Among the silane coupling agents, A1S with high polarity and amino groups exhibited the most significant improvement. While A2S, with more amino groups than A1S, showed less improvement, ES with polar epoxide groups also enhanced the interfacial bonding strength between SUS and PA 6,6. These findings confirm the effectiveness of surface treatment and the role of polar silane coupling agents as compatibilizers. To enhance the bonding strength of SUS/PA 6,6, the epoxy resin containing different curing agents was used. The bonding strength varied with curing agents. The epoxy resin containing anhydride-based agents, despite high adhesive properties, showed lower compatibility with SUS, thereby reducing the bonding strength. In contrast, the epoxy resin comprising acid or amine curing agents exhibited better performance. The study confirmed that the use of proper curing agents can improve the bonding strength by approximately 2-4 MPa. However, the incorporation of SAc and AcAn exhibited the lowest mechanical properties. The research explored the interfacial compatibilities in polymer blends and composites, and heterojunction composites.

AC Dielectric Breakdown Strength of Extra-high-voltage Cables Semiconductive Compounds Filled with Surface-treated MWCNTs

Jiho Park 고려대학교 대학원 2024 국내석사

Extra High Voltage (EHV) cables demand a semiconductor layer that serves crucial functions such as electric field mitigation, partial discharge prevention, and insulation protection. The base resin employed for this purpose is typically poly(ethylene-co-butyl acrylate) (EBA), with the addition of carbon black (CB) to augment electrical conductivity. A hybrid nanocarbon composite is developed by introducing multi-walled carbon nanotubes (MWCNTs) as a secondary conductive filler. The blending of MWCNTs with carbon black aims to strike an optimal balance in carbon filler content and establish a favorable ratio. This innovative approach seeks to enhance the overall performance of EHV cables, offering a potential solution to the trade-off between electrical conductivity and material properties. One of the main challenges in carbon nanotube research field is the dispersion and stabilization of MWCNTs. Inadequate filler dispersion may result in a reduction of the composite's characteristics, impacting both its stability and durability. In this paper, pyrene-poly(dimethylaminoethyl methacrylate)-b-poly(methyl methacrylate)(py-PDMAEMA-b-PMMA) compatibilizer based on polymers was synthesized with the aim of improving the dispersion between the filler and the matrix. Designed with intention, this compatibilizer features a polymer structure where pyrene-PDMAEMA block containing conjugated polymers, intimately interacts with forming strong pi–pi stack interactions at the walls of carbon nanotubes, while the other blocks, PMMA, enhance solubility by creating a steric barrier or repulsion interaction between polymer-wrapped nanotubes. Therefore, the application of py-PDMAEMA-b-PMMA compatibilizer to the MWCNTs surface can ensure dispersibility. To find out the effect on the insulation properties such as insulation resistance according to the performance of the semiconductor layer, the AC dielectric breakdown strength was measured after modifying the MWCNTs surface with a compatibilizer. In addition, a double interface sample of an insulating compound and a semiconductive compound was newly presented. By presenting these samples, the reliability of measuring the AC dielectric breakdown strength was increased by lowering the probability of creepage failure. Experimental data on AC dielectric breakdown strength were evaluated for reliability using Weibull distribution.

폴리프로필렌/클레이 나노복합체의 기계적 및 유변학적 물성에 미치는 PP-g-(Maleic anhydride/Styrene)계 상용화제의 영향

김민정 전북대학교 대학원 2007 국내석사

Polypropylene (PP) is one of the most important general purpose polymers widely used in various industrial fields. For an enhanced performance on thermal and mechanical properties of PP, many efforts have been made for nanocomposites with clays. But, the different nature of polarity between PP and clays has been an obstacle which should be solved for a reasonable dispersion and degree of exfoliation of clay layers. A graft copolymerization of polar component, notably maleic anhydride(MA) onto PP main chain has been reported to show a reasonable compatibilizing effects. In this study, a new compatibilizer was synthesized by grafting MA and styrene(ST) onto the PP main chain. A new compatibilizer based on maleic anhydride (MA) and styrene (ST)-grafted polypropylene (PP) was synthesized for enhancing the properties of PP/clay nanocomposites. About 20% improvement in tensile strength was found due to an improved dispersion and exfoliation of clay layers. The prepared PP-g-MA/ST can be a promising way to compatibilize the PP/Clay system.f