In order to solve the problems generated by plastic waste, many efforts have been done to obtain an environmental friendly material. Most of the researches are focused on substitution of the petro-based plastics by biodegradable materials with similar properties and low in cost [1–3]. Among the natural polymers, starch has been considered as one of the most promising candi- dates for this regard because of its attractive combination of price, abundance and thermoplastic behavior, in addition to biodegrad- ability. The main disadvantage of biodegradable starch-based films is their hydrophilic character, which leads to low stability when these materials are submitted to different environmental condi- tions [4]. In addition, starch-based materials have poor mechanical properties and particularly poor elongation (around 6%) at ambi- ent conditions. Thus, the incorporation of a plasticizer is required to overcome the brittleness of these materials. Plasticizers reduce intermolecular forces and increase the mobility of polymer chains, decreasing the glass transition temperature (Tg ) and increasing per- meability [5].
Nanotechnology is the control or manipulation of matter at the atomic, molecular, or macromolecular level, in which one of the components affects functional behavior. Development of the polymer–clay nanocomposites is one of the latest revolution- ary steps of the polymer technology. Preparations of blends or nanocomposites using inorganic or natural fibers are the route to improve some of the properties of biodegradable polymers. Nanocomposites are thermoplastic polymers which have nanoscale inclusions, 2–8% by weight. The addition of low percentages of clay to polymers may cause to increase mechanical strength; reduce weight; increase heat resistance; and improve barrier against mois- ture, oxygen, carbon dioxide, ultraviolet radiation, and volatiles of food package materials in comparison to traditional composites. Montmorillonite (MMT) is the most commonly used layered sili- cates because it is environmentally friendly and readily available in large quantities with relatively low cost. Therefore, it is possi- ble to improve the properties of starch polymer by the addition of small amounts of MMT [6–8].
Other approach to improve the functional properties of the starch films is to blend starch with other polymers. However, most of the synthetic polymers are hydrophobic and thermodynami- cally immiscible with hydrophilic starch. For this reason, simple mixing will result in phase incompatibility and poor mechanical properties. Accordingly, the current research is focused to the use of biodegradable relatively hydrophilic polymers and fibers, which lead to the fabrication of highly environmental respectful biocom- posites [9,10]. Carboxymethyl cellulose (CMC) is cellulose ether that exhibits thermal gelation and forms excellent films. Because of its polymeric structure and high molecular weight, it is capable to use as a filler in biocomposite films production. CMC is able to improve the mechanical and barrier properties of the starch-based films [11]. Citric acid (CA) recognized as a cross-linking agent for starch modification. Because of the multi-carboxyl structure, CA may serve as a cross-linking agent and the carboxyl groups on CA can form stronger hydrogen bonds between the hydroxyl groups on starch molecules and hence, it may improve the mechanical properties and water resistibility [12,13].
There are few papers about the use of carboxymethyl cellulose (CMC) as reinforcing filler in a starch matrix. On the other hand, to the best of our knowledge, there is no specific study on the effects of nanoclay on the physical properties of starch–CMC biocomposite films. The aim of this research work is study of the structural, barrier, mechanical and thermal properties of glycerol plasticized and CA modified starch–CMC–MMT bionanocomposites.
เพื่อแก้ปัญหาที่สร้างขึ้น โดยขยะพลาสติก ความพยายามจำนวนมากได้รับวัสดุเป็นมิตรสิ่งแวดล้อม ส่วนใหญ่ของงานวิจัยมีความสำคัญในการทดแทนพลาสติกจากเปโตร โดยสลายวัสดุ มีคุณสมบัติคล้ายคลึงกัน และต่ำสุดในต้นทุน [1-3] ระหว่างโพลิเมอร์ธรรมชาติ แป้งได้รับการพิจารณาเป็นหนึ่งในแคนดิวันว่าสำหรับเรื่องนี้เนื่องจากการรวมกันที่น่าสนใจของราคา ความอุดมสมบูรณ์ และ ลักษณะเทอร์โมพลาสติก นอกจากความสามารถในการ biodegrad ข้อเสียหลักของฟิล์มจากแป้งย่อยสลายยากเป็นของอักขระ hydrophilic ซึ่งนำไปสู่ความมั่นคงต่ำเมื่อวัสดุเหล่านี้จะถูกส่งไปต่างสิ่งแวดล้อมเบาะ ๆ ว่าพวกเขา-tions [4] วัสดุที่ใช้แป้งมีคุณสมบัติทางกลที่ดีและไม่ดีโดยเฉพาะอย่างยิ่ง elongation (ประมาณ 6%) เงื่อนไข ambi เอนท์ ดังนั้น ในการประสานความกระด้างไนลจะต้องเอาชนะเปราะของวัสดุเหล่านี้ Plasticizers ลดกอง intermolecular และเพิ่มความคล่องตัวของโซ่พอลิเมอร์ ลดอุณหภูมิการเปลี่ยนแก้ว (Tg) และเพิ่มขึ้นต่อ meability [5]Nanotechnology is the control or manipulation of matter at the atomic, molecular, or macromolecular level, in which one of the components affects functional behavior. Development of the polymer–clay nanocomposites is one of the latest revolution- ary steps of the polymer technology. Preparations of blends or nanocomposites using inorganic or natural fibers are the route to improve some of the properties of biodegradable polymers. Nanocomposites are thermoplastic polymers which have nanoscale inclusions, 2–8% by weight. The addition of low percentages of clay to polymers may cause to increase mechanical strength; reduce weight; increase heat resistance; and improve barrier against mois- ture, oxygen, carbon dioxide, ultraviolet radiation, and volatiles of food package materials in comparison to traditional composites. Montmorillonite (MMT) is the most commonly used layered sili- cates because it is environmentally friendly and readily available in large quantities with relatively low cost. Therefore, it is possi- ble to improve the properties of starch polymer by the addition of small amounts of MMT [6–8].Other approach to improve the functional properties of the starch films is to blend starch with other polymers. However, most of the synthetic polymers are hydrophobic and thermodynami- cally immiscible with hydrophilic starch. For this reason, simple mixing will result in phase incompatibility and poor mechanical properties. Accordingly, the current research is focused to the use of biodegradable relatively hydrophilic polymers and fibers, which lead to the fabrication of highly environmental respectful biocom- posites [9,10]. Carboxymethyl cellulose (CMC) is cellulose ether that exhibits thermal gelation and forms excellent films. Because of its polymeric structure and high molecular weight, it is capable to use as a filler in biocomposite films production. CMC is able to improve the mechanical and barrier properties of the starch-based films [11]. Citric acid (CA) recognized as a cross-linking agent for starch modification. Because of the multi-carboxyl structure, CA may serve as a cross-linking agent and the carboxyl groups on CA can form stronger hydrogen bonds between the hydroxyl groups on starch molecules and hence, it may improve the mechanical properties and water resistibility [12,13].มีเอกสารน้อยเกี่ยวกับ carboxymethyl เซลลูโลส (CMC) การใช้เป็นฟิลเลอร์เสริมในเมทริกซ์แป้ง บนมืออื่น ๆ กับความรู้ของเรา ได้ศึกษาผลของ nanoclay สมบัติทางกายภาพของฟิล์มแป้ง – CMC biocomposite ไม่ระบุ จุดมุ่งหมายของงานวิจัยนี้เป็นการศึกษาโครงสร้าง อุปสรรค plasticized คุณสมบัติทางกล และความร้อนของกลีเซอร และ CA แก้ไข bionanocomposites แป้ง – CMC – MMT
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