Abstract:This study investigates the physical and mechanical properties of nanostructured films produced from Pinus sp. kraft pulp. To obtain the nanocellulose, the bleached kraft pulp was submitted to six different grinding regimes: two, five, ten, 20, 30, and 40 passes through the grinder. The influence of the number of passes was evaluated through the films’ physical and mechanical properties. The results show that the nanofibers reduced the thickness and considerably increased the density values of the fabricated f… Show more
“…The bleached MFC had an increase in ICr after the mechanical defibrillation process, which resulted in greater exposure of the fibrils than in the cellulose fiber sample, increasing its ICr, but did not cause fiber degradation and tearing to the point of affecting the index. Lengowski et al (2018) and Viana et al (2019) found ICr values close to 80 % for unbleached pine cellulose fiber, near those found in work, which is consistent with other published studies.…”
Section: Table 3: Crystallinity Index Of Cellulose Fibers and Suspens...supporting
The wood is exposed to possible damages caused by weather, requiring the application of a finishing coat to provide extra protection. The aim of this work was to evaluate the influence of the addition of microfibrillated cellulose in waterborne varnish on the colorimetric parameters, wettability and finish characteristics of wood products. Color was evaluated with a CM-5 spectrophotometer; surface wettability was analyzed by contact angle measurement using a drop shape analysis goniometer; and abrasion, adhesion and impact tests were performed to evaluate the quality of the coating. The coating's optical characteristics were not affected by the addition of microfibrillated cellulose. The changes in wood wettability were small, with no statistical difference between the wood treated with plain varnish and that with unbleached microfibrillated cellulose. In the analysis of the variation of the contact angle during the elapsed time, the coating containing unbleached microfibrillated cellulose presented the best results. The results of finish quality did not show numerical changes after the addition of the microfibrillated cellulose, but qualitatively the microfibrillated cellulose caused better anchoring of the coating to the specimens. Therefore, the use of microfibrillated cellulose as reinforcement in coatings has potential, but tests with different consistencies and tests of other properties are necessary.
“…The bleached MFC had an increase in ICr after the mechanical defibrillation process, which resulted in greater exposure of the fibrils than in the cellulose fiber sample, increasing its ICr, but did not cause fiber degradation and tearing to the point of affecting the index. Lengowski et al (2018) and Viana et al (2019) found ICr values close to 80 % for unbleached pine cellulose fiber, near those found in work, which is consistent with other published studies.…”
Section: Table 3: Crystallinity Index Of Cellulose Fibers and Suspens...supporting
The wood is exposed to possible damages caused by weather, requiring the application of a finishing coat to provide extra protection. The aim of this work was to evaluate the influence of the addition of microfibrillated cellulose in waterborne varnish on the colorimetric parameters, wettability and finish characteristics of wood products. Color was evaluated with a CM-5 spectrophotometer; surface wettability was analyzed by contact angle measurement using a drop shape analysis goniometer; and abrasion, adhesion and impact tests were performed to evaluate the quality of the coating. The coating's optical characteristics were not affected by the addition of microfibrillated cellulose. The changes in wood wettability were small, with no statistical difference between the wood treated with plain varnish and that with unbleached microfibrillated cellulose. In the analysis of the variation of the contact angle during the elapsed time, the coating containing unbleached microfibrillated cellulose presented the best results. The results of finish quality did not show numerical changes after the addition of the microfibrillated cellulose, but qualitatively the microfibrillated cellulose caused better anchoring of the coating to the specimens. Therefore, the use of microfibrillated cellulose as reinforcement in coatings has potential, but tests with different consistencies and tests of other properties are necessary.
“…Too much exudate can cause skin maceration or infection, on the contrary, allowing the wound to become very dry can slow down the healing process (Chinga-Carrasco and Syverud 2014; Gustaite et al 2015;Basu et al 2017a). The water absorption determined by the Cobb method was 78 g m -2 , which is similar to the value of 85.7 g m -2 obtained by Viana et al (2019) for 60 g m -2 nanocellulose film. The smaller grammage of the films compared to Viana et al (2019) allows for similar absorption, however more pliable, which was beneficial from a dressing usage point of view.…”
Large wounds are characterized by clinical and surgical challenges, requiring numerous searches on demand for inexpensive biocompatible materials that produce the best quality of cutaneous healing. Cellulose is a biopolymer of greatest abundance, good biocompatibility and wide application due to its chemical and physical properties. This study was aimed to develop and characterize low cost membranes of wood cellulose nanofibrils for potential
“…Those parameters were established based on previous studies (Viana et al 2019). Before, the material presented a liquid aspect and, after passing through the mill, the resulting material presents a gel aspect.…”
“…Nanocellulose thin lms were prepared with 2 % of total solid content based on the literature (Viana et al 2019). The procedure comes from the protocol 2540 G from APHA (1998) and it is described in the SI.…”
In the past few decades, technological advances have aroused the interest of industries and consumers for exible electronic devices. However, the substrates currently used, such as glass and polyethylene terephthalate (PET), present problems regarding their performance and destination, since the rst is di cult to handle and the second comes from non-renewable sources. Common properties required in substrates to provide their use in organic electronics are exibility, stability and su cient transparency. Therefore, as a sustainable and e cient alternative, the present study aimed to develop a totally cellulose-based substrate, a natural abundant polymer that presents thermal stability, mechanical strength, recyclability and is biodegradable. It was produced different substrates using micro brils from Eucalyptus sp. A pure micro ber substrate weighing 25 g m -² was obtained by the vacuum ltration method and paper-forming machine. The other four substrates were obtained by the casting method containing cellulose acetate matrix and freeze-dried micro brils reinforcement at different concentrations. In addition, a substrate containing 1.0 % of the suspended micro brils as reinforcement in the cellulose acetate matrix was produced. A conductive thin lm of Poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (PEDOT:PSS) was deposited by air-brush technique as an electrode to evaluate the electrical performance of the substrates. The obtained lms were characterized by their optical, thermal and morphological properties, showing a great potential to be used as substrate in organic electronic devices.
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