بررسی خصوصیات فیزیکی و مکانیکی فیلم‌ بایونانو کامپوزیت بر پایه‌ی موسیلاژ کتان و نانوکریستال سلولز

تولیدکنندگان در تلاش هستند تا فیلم‌های زیست تخریب‌پذیر و خوراکی را جایگزین مواد پلاستیکی در صنعت بسته‌بندی مواد غذایی کنند. هدف از این تحقیق، تولید و مشخصه‌سازی فیلم خوراکی و زیست تخریب‌پذیر بر پایه ترکیب صمغ دانه کتان و نانوکریستال سلولز بود. فیلم‌ها از نسبت‌های مختلف (0:100، 30:70، 50:50، 70:30 و 100:0) محلول‌های موسیلاژ دانه کتان (2 درصد وزنی/حجمی) و نانوکریستال سلولز (6 درصد وزنی/حجمی) تهیه شد و خصوصیات فیزیکی، رنگی و مکانیکی آنها مورد بررسی قرار گرفت و بهترین نسبت برای تهیه فیلم بایونانوکامپوزیت انتخاب گردید. ریزساختار فیلم تولیدی با استفاده از میکروسکوپ الکترونی روبشی (sem) مورد مطالعه قرار گرفت. میانگین داده‌ها، توسط آنالیز تجزیه واریانس در طرح کاملاً تصادفی و با استفاده از نرم‌افزار spss 22.0 تجزیه و تحلیل شدند. تفاوت‌های بین تیمارها، در آزمون چنددامنه‌ای دانکن و در سطح احتمال 95 درصد بیان گردید (0.05>p) و نمودارهای مربوطه با excel 2013 رسم شدند. نتایج نشان داد که با افزودن نانوکریستال سلولز به فیلم بر پایه موسیلاژ دانه کتان و افزایش میزان آن، شدت روشنایی فیلم‌ها کاهش و شدت قرمزی، زردی و کدورت فیلم‌ها به‌طور معنی‌داری افزایش یافت (0.05>p). نتایج حاصل در نهایت نشان داد که ترکیب موسیلاژ دانه کتان و نانوکریستال سلولز در نسبت 30:70 توانست بهترین فیلم از لحاظ استحکام مکانیکی و پایداری در مقابل رطوبت و بخارآب را تولید کند. تصویر sem این فیلم بیانگر سطح صاف، هموار و توزیع یکنواخت نانوکریستال‌ها در شبکه فیلم بود.

investigating physical and mechanical properties of bionanocomposite film based on flaxseed mucilage and cellulose nanocrystal

introduction  manufacturers are trying to replace plastic materials in the food packaging industry with biodegradable and edible films. biodegradable edible films and coatings are mainly made from carbohydrates, lipids and proteins and their mixtures. in recent decades, various carbohydrates from plant sources have been investigated and introduced as new compounds for the preparation of these films. flaxseed gum is a white to cream-colored powder that dissolves in water and produces a gel, and is a desirable compound for forming films and coatings. recently, through the integration of reinforcements or fillers with at least one nanometer dimension in the substrate of one or more natural biopolymers, the physicochemical, mechanical, optical, thermal and barrier properties of pure biofilms have been improved. the use of cellulose nanoparticles in biofilms as a reinforcing agent for polymer materials leads to the creation of composite films with better quality characteristics and leads to the creation of functionalization activities in film production. therefore, the aim of this research was to produce and characterize edible and biodegradable film based on the combination of flaxseed gum and cellulose nanocrystals.materials and methods cellulose nanocrystals (degree of crystallinity: 42% and average particle size: 58 nm) were extracted from cotton linters. glycerol and other chemicals used for this research were obtained from merck, germany. flaxseeds were purchased from the local market of shiraz (iran). bionanocomposite films were prepared from different ratios (0:100, 30:70, 50:50, 70:30 and 100:0) of flaxseed mucilage (2% w/v) and cellulose nanocrystal (6% w/v) solutions. the prepared solutions were poured on a petri dish with a diameter of 15 cm and dried in an oven at 80°c for 4 hours. their physical, color and mechanical properties were investigated and the best ratio was selected for the preparation of bionanocomposite film. the produced films were subjected to different analysis to determine thickness, solubility, water absorption capacity, permeability to water vapor, tensile strength, elongation at break point, and colorimetry. the microstructure of the produced film was studied using a scanning electron microscopy (sem).the average data were analyzed by analysis of variance in a completely randomized design using spss 22.0 software. differences between treatments were expressed in duncan’s multiple range test at the 95% probability level (p<0.05) and the corresponding graphs were drawn with excel 2013.results and discussion  the results of the film thickness test showed that the film containing 100% mucilage has the lowest thickness and with the addition of cellulose nanocrystals, the thickness increased significantly (p<0.05). the results of the water solubility and water absorption capacity of the film samples showed that the addition of cellulose nanocrystals to the flaxseed mucilage film initially led to a significant decrease in the water solubility and water absorption capacity (p<0.05), so that the lowest level ofthese two physical parameters were obtained in the film containing the combination of 70% flaxseed mucilage and 30% cellulose nanocrystal, and then with the increase of cellulose nanocrystals, an increase in water solubility and water absorption capacity of the films was observed. nanocrystal cellulose at low levels (30%) acted as a filler and was uniformly dispersed in the network of the film and by filling the empty pores of the biopolymer film based on flaxseed mucilage, it caused the transfer of water vapor more complicated and reduced the permeability to water vapor. however, its higher amount increased the permeability of the film to water vapor.