Reaktif ekstrüzyon yöntemi ile PA6/vermikülit kompozitlerin hazırlanması ısıl, morfolojik ve mekanik özelliklerinin belirlenmesi
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Dosyalar
Tarih
2023
Yazarlar
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Yayıncı
Bursa Teknik Üniversitesi, Lisansüstü Eğitim Enstitüsü
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Polimerik malzemelerin kullanımı yüksek korozyon direnci, düşük yoğunluk, kolay şekillendirilme, geri dönüştürülebilme gibi üstün özellikleri sayesinde gün geçtikçe artmaktadır. Ancak birçok uygulamada aranan özelliklerin tek başına bir polimerde bulunması zordur. Bu nedenle polimerlere farklı özellikler kazandırmak amacıyla polimer kompozitlerin hazırlanması oldukça etkili ve yaygın bir yöntemdir. Polimere lif, seramik, metal ve kil gibi diğer bileşenler katılarak kompozitler hazırlanmaktadır. Hazırlanan kompozitlerin ısıl, mekanik, dielektrik, elektronik, manyetik gibi birçok özellikleri araştırılmaktadır. Belirlenen özelliklerine göre polimer kompozitler biyomedikal, optik, savuma sanayi, elektromanyetik kalkanlama, sensör, yapı ve inşaat, piller, elektronik bileşenler gibi birçok uygulamada kullanılmaktadır. Poliamid 6 (PA6) üstün mekanik özellikleri ve yüksek servis sıcaklığı özellikleri sayesinde havacılık, otomotiv ve beyaz eşya olmak üzere birçok sektörde kullanılmaktadır. Ancak birçok polimer gibi petrol türevi olduğundan ısıl bozunmaya karşı dirençleri düşüktür. Bu yönleri ise kullanım alanlarını kısıtlamaktadır. Bu nedenle son zamanlarda PA6'nın ısıl bozunmaya karşı direncini artırmaya yönelik çalışmalar artmıştır. Ayrıca sektörel bazda kullanımları iyileştirmek için çeşitli PA6 kompozitleri üzerinde araştırmalar yapılmıştır. Hafif olması, maliyetinin piyasa koşullarına göre uygun olması nedeniyle PA6'nın mekaniksel özelliklerini iyileştirme açısından son zamanlarda kil kullanımı tercih sebebi haline gelmiştir. Bu killer arasında vermikülit düşük yoğunluk, düşük maliyet, termal kararlılık gibi özelliklerinin yanı sıra son yıllarda yanma geciktirici özelliği de keşfedilmiştir. Bu tez çalışmasında PA6'nın ısıl ve mekanik özelliklerini iyileştirmek, ayrıca karbon ayak izini ve maliyetini düşürmek amacıyla kütlece %5 ve 10 vermikülit katkılanarak polimer/kil kompozitleri hazırlanmıştır. Kompozitlerde 3-glisidoksipropiltrimetoksisilan (GPTMS) ajanı vermikülit ve PA6 arasında kimyasal bağlanma sağlanması için kullanılmıştır. Ayrıca silan ajanı varlığının etkisini araştırmak için sadece kil ve PA6 içeren kompozitler de hazırlanmıştır. Öncelikle silan ajanı/kil karışımları püskürtme yöntemi ile hazırlanmış sonrasında PA6 ilavesiyle hazırlanan nihai karışım çift vidalı ekstrüder kullanılarak eriyik karıştıma yöntemi ile kompozitler hazırlanmıştır. Eriyik karıştırma aşamasında silan ajanının metoksisilan kısımlarından kil yüzeylerine, epoksi kısmından ise PA6'ya kovalent bağlarla bağlanması sağlanarak reaktif ekstrüzyon işlemi gerçekleştirilmiştir. Kompozitlere ait ATR-FTIR spektrumlarından ekstrüzyon öncesi püskürtme yöntemi ile hazırlanan vermükülit-GPTMS karışımında her iki bileşenden gelen karakteristik piklerin çıktığı görülmüş böylece karışımın başarılı bir şekilde hazırlandığı anlaşılmıştır. Kompozitlere ait spektrumlarda Si-O-Si titreşimine ait karakteristik pik şiddetinin kil oranı ile beklenildiği gibi arttığı görülmüştür. Kompozitlerin XRD sonuçlarından PA6 ve vermikülit karakteristik pikleri görülürken, vermikülite ait piklerin kompozitteki miktarı ile arttığı anlaşılmıştır. Numunelere ait SEM görüntülerinden silan ajanının olduğu kompozitlerde vermikülit ile PA6 arasında kimyasal bağlanmaların olduğuna dair kanıtlar net bir şekilde görülmüştür. DSC sonuçlarından PA6 ve kompozitlerin erime sıcaklıklarında önemli bir değişme olmadığı, kil miktarının ve silan ajanı kullanımının kristaliniteyi arttırdığı sonucuna ulaşılmıştır. Çekme testlerinden elastik modül değerlerinin kil oranı ile arttığı ve silan ajanı varlığı ile pek değişmediği, kopma dayanımının kil oranı ve silan ajanı ile arttığı tespit edilmiştir. Kopma uzaması değerlerinin silan ajanı bulunan ve %5 kil içeren numunede ham PA6'ya göre yaklaşık 7 kat arttığı belirlenmiştir. Bu artışın silan ajanı varlığında PA6 ile vermikülit arasındaki kimyasal bağlanmadan ileri geldiği değerlendirilmiştir. Böylece PA6/vermikülit kompozitleri hazırlayarak mekanik özellikleri iyileştirilmiş, karbon ayak izi azaltılmış ve maliyeti düşürülmüş birçok sektörde kullanılabilecek hammadde geliştirilmiştir.
The use of polymeric materials is increasing day by day thanks to their superior properties such as high corrosion resistance, low density, easy shaping and recyclability. However, the properties sought in many applications are difficult to find in a polymer alone. For this reason, the preparation of polymer composites is a very effective and common method to impart different properties to polymers. Composites are prepared by adding other components such as fiber, ceramic, metal and clay to the polymer. Many properties of the prepared composites such as thermal, mechanical, dielectric, electronic and magnetic are investigated. According to their determined properties, polymer composites are used in many applications such as biomedical, optics, defense industry, electromagnetic shielding, sensors, building and construction, batteries, electronic components. Polyamide 6 (PA6) is used in many sectors such as aviation, automotive and white goods, thanks to its superior mechanical properties and high service temperature properties. However, since they are petroleum derivatives like many polymers, their resistance to thermal degradation is low. These aspects limit its usage areas. For this reason, studies on increasing the resistance of PA6 to thermal degradation have increased recently. Additionally, research has been conducted on various PA6 composites to improve their use on a sectoral basis. Recently, the use of clay has become preferred in terms of improving the mechanical properties of PA6 due to its light weight and affordable cost compared to market conditions. Among these clays, vermiculite, in addition to its properties such as low density, low cost and thermal stability, has also been discovered in recent years for its fire retardant properties. In this thesis study, polymer/clay composites were prepared by adding 5 and 10% vermiculite by mass in order to improve the thermal and mechanical properties of PA6 and also to reduce its carbon footprint and cost. In the composites, 3-glycidyloxypropyl)trimethoxysilane (GPTMS) agent was used to provide chemical bonding between vermiculite and PA6. In addition, composites containing only clay and PA6 were also prepared to investigate the effect of the presence of silane agent. Firstly, silane agent/clay mixtures were prepared by spraying method, and then the final mixture prepared with the addition of PA6 was prepared by the melt mixing method using a twin screw extruder. In the melt mixing stage, reactive extrusion process was carried out by covalently binding the silane agent to the clay surfaces from the methoxysilane parts and to PA6 from the epoxy part. From the ATR-FTIR spectra of the composites, it was seen that characteristic peaks from both components appeared in the vermuculite-GPTMS mixture prepared by the pre-extrusion spraying method, thus it was understood that the mixture was prepared successfully. In the spectra of the composites, it was observed that the characteristic peak intensity of the Si-O-Si vibration increased with the clay ratio, as expected. While the characteristic peaks of PA6 and vermiculite were seen from the XRD results of the composites, it was understood that the peaks of vermiculite increased with the amount in the composite. From the SEM images of the samples, evidence of chemical bonding between vermiculite and PA6 in the composites containing the silane agent was clearly seen. From the DSC results, it was concluded that there was no significant change in the melting temperatures of PA6 and composites, and that the amount of clay and the use of silane agent increased the crystallinity. From the tensile tests, it was determined that the elastic modulus values increased with the clay ratio and did not change much with the presence of silane agent, and the tensile strength increased with the clay ratio and silane agent. It was determined that the elongation at break values increased approximately 7 times in the sample containing silane agent and 5% clay compared to neat PA6. It was evaluated that this increase was due to the chemical bonding between PA6 and vermiculite in the presence of silane agent. Thus, by preparing PA6/vermiculite composites, raw materials that can be used in many sectors have been developed, with improved mechanical properties, reduced carbon footprint and cost.
The use of polymeric materials is increasing day by day thanks to their superior properties such as high corrosion resistance, low density, easy shaping and recyclability. However, the properties sought in many applications are difficult to find in a polymer alone. For this reason, the preparation of polymer composites is a very effective and common method to impart different properties to polymers. Composites are prepared by adding other components such as fiber, ceramic, metal and clay to the polymer. Many properties of the prepared composites such as thermal, mechanical, dielectric, electronic and magnetic are investigated. According to their determined properties, polymer composites are used in many applications such as biomedical, optics, defense industry, electromagnetic shielding, sensors, building and construction, batteries, electronic components. Polyamide 6 (PA6) is used in many sectors such as aviation, automotive and white goods, thanks to its superior mechanical properties and high service temperature properties. However, since they are petroleum derivatives like many polymers, their resistance to thermal degradation is low. These aspects limit its usage areas. For this reason, studies on increasing the resistance of PA6 to thermal degradation have increased recently. Additionally, research has been conducted on various PA6 composites to improve their use on a sectoral basis. Recently, the use of clay has become preferred in terms of improving the mechanical properties of PA6 due to its light weight and affordable cost compared to market conditions. Among these clays, vermiculite, in addition to its properties such as low density, low cost and thermal stability, has also been discovered in recent years for its fire retardant properties. In this thesis study, polymer/clay composites were prepared by adding 5 and 10% vermiculite by mass in order to improve the thermal and mechanical properties of PA6 and also to reduce its carbon footprint and cost. In the composites, 3-glycidyloxypropyl)trimethoxysilane (GPTMS) agent was used to provide chemical bonding between vermiculite and PA6. In addition, composites containing only clay and PA6 were also prepared to investigate the effect of the presence of silane agent. Firstly, silane agent/clay mixtures were prepared by spraying method, and then the final mixture prepared with the addition of PA6 was prepared by the melt mixing method using a twin screw extruder. In the melt mixing stage, reactive extrusion process was carried out by covalently binding the silane agent to the clay surfaces from the methoxysilane parts and to PA6 from the epoxy part. From the ATR-FTIR spectra of the composites, it was seen that characteristic peaks from both components appeared in the vermuculite-GPTMS mixture prepared by the pre-extrusion spraying method, thus it was understood that the mixture was prepared successfully. In the spectra of the composites, it was observed that the characteristic peak intensity of the Si-O-Si vibration increased with the clay ratio, as expected. While the characteristic peaks of PA6 and vermiculite were seen from the XRD results of the composites, it was understood that the peaks of vermiculite increased with the amount in the composite. From the SEM images of the samples, evidence of chemical bonding between vermiculite and PA6 in the composites containing the silane agent was clearly seen. From the DSC results, it was concluded that there was no significant change in the melting temperatures of PA6 and composites, and that the amount of clay and the use of silane agent increased the crystallinity. From the tensile tests, it was determined that the elastic modulus values increased with the clay ratio and did not change much with the presence of silane agent, and the tensile strength increased with the clay ratio and silane agent. It was determined that the elongation at break values increased approximately 7 times in the sample containing silane agent and 5% clay compared to neat PA6. It was evaluated that this increase was due to the chemical bonding between PA6 and vermiculite in the presence of silane agent. Thus, by preparing PA6/vermiculite composites, raw materials that can be used in many sectors have been developed, with improved mechanical properties, reduced carbon footprint and cost.
Açıklama
Anahtar Kelimeler
Polimer Bilim ve Teknolojisi, Polymer Science and Technology
