scholarly journals INVESTIGATION OF THE DENSITY OF A FIBROUS CELLULOSE MATRIX FOR A HEAT-INSULATING POLYMER COMPOSITE MATERIAL AT LOW PRESSING PRESSURES

2021 ◽  
pp. 118-125
Author(s):  
Д.В. Чащилов ◽  
Л.А. Злочевский ◽  
А.Е. Струкова ◽  
И.Н. Павлов
Keyword(s):  
Experimental Study ◽  
Bulk Density ◽  
Polymer Composite ◽  
Experimental Studies ◽  
Cellulose Fiber ◽  
Cellulose Fibers ◽  
Polymer Composite Material ◽  
Pressing Pressure ◽  
Second Stage ◽  
Coniferous Wood

Для теплоизоляционных полимерных композиционных материалов (ПКМ) с наполнителем из целлюлозных волокон одним из актуальных вопросов является изменение плотности волокнистой матрицы под действием внешних механических нагрузок. Предметом экспериментального исследования явились образцы разрыхленной небелёной древесной сульфитной целлюлозы из хвойной древесины в воздушно-сухом состоянии. Цель исследования – оценка изменения насыпной плотности разрыхленной целлюлозы от величины давления прессования при малых давлениях прессования. В экспериментальных исследованиях использован метод денсиметрии. Из целлюлозной папки в лабораторных условиях получены образцы разрыхленной целлюлозы путём механического разволокнения. Использован лабораторный колковый рыхлитель роторного действия. Разрыхление проведено при окружной скорости ротора 50 м/с. Давление прессования варьировалось от 0 до 7,5 кПа. Получены образцы разрыхленноё целлюлозы с насыпной плотностью от 11,1 до 100,0 кг/м3. Эксперименты проведены с трёхкратным повторением. Показано, что при увеличении давления прессования насыпная плотность целлюлозы стабильно возрастает. В исследованном диапазоне давлений прессования уплотнение целлюлозы проходит в два этапа. На первом этапе при давлении прессования от 0 до 5 кПа насыпная плотность возрастает от 11,1 до 87,5 кг/м3. На втором этапе, при давлении прессования свыше 5 кПа, насыпная плотность возрастает с 87,5 до 100 кг/м3. На втором этапе замедление нарастания насыпной плотности при росте давления прессования может быть обусловлено деформацией элементарных волокон целлюлозы. Результаты экспериментального исследования могут быть применены для создания теплоизоляционных ПКМ на основе целлюлозных волокон. For heat-insulating polymer composite materials (PCM) with a cellulose fiber filler, one of the topical issues is the change in the density of the fiber matrix under the influence of external mechanical loads. The subject of the experimental study was samples of loosened unbleached wood sulfite cellulose from coniferous wood in an air-dry state. The aim of the study is to assess the change in the bulk density of loosened pulp from the value of the pressing pressure at low pressing pressures. In experimental studies, the method of densimetry was used. Samples of loosened cellulose were obtained from the pulp folder under laboratory conditions by mechanical de-fibration. A laboratory rotary chopper was used. Loosening was carried out at a circumferential rotor speed of 50 m / s. The pressing pressure varied from 0 to 7.5 kPa. Samples of loosened cellulose with a bulk density from 11.1 to 100.0 kg/m3were obtained. The experiments were carried out in three-fold repetition. It is shown that with an increase in the pressing pressure, the bulk density of cellulose steadily increases. In the studied range of pressing pressures, the pulp compaction takes place in two stages. At the first stage, at a pressing pressure of 0 to 5 kPa, the bulk density increases from the initial value 11.1 to 87.5 kg / m3. At the second stage, when the pressing pressure exceeds 5 kPa, the bulk density increases from 87.5 to 100 kg/ m3. At the second stage, the slowdown in the increase in bulk density with an increase in the pressing pressure can be caused by the deformation of the elementary cellulose fibers. The results of the experimental study can be used to create heat-insulating PCM based on cellulose fibers.

scholarly journals DETERMINATION OF DEFORMATION IN MESH COMPOSITE STRUCTURE UNDER THE ACTION OF COMPRESSIVE LOADS

2020 ◽  
Vol 17 (35) ◽  
pp. 599-608 ◽  
Author(s):  
Alexander A. OREKHOV ◽  
Yuri A. UTKIN ◽  
Polina F. PRONINA
Keyword(s):  
Composite Material ◽  
Carbon Fiber ◽  
Bearing Capacity ◽  
Polymer Composite ◽  
Experimental Studies ◽  
Polymer Composite Material ◽  
Lightweight Mesh ◽  
Carbon Filler ◽  
Selection Of

One of the significant innovative technologies is the creation of large-sized structures that work for a long time in space and meet stringent restrictions on overall mass characteristics. Among these structures, in the first place, is the section of bearing truss (BT). This article presents the results of experimental studies of sectors of load-bearing trusses of mesh design for compression. Recently, composite mesh cylindrical shells are used as spacecraft housings. The mesh shell is a supporting structure to which the instruments and mechanisms of the spacecraft are attached. The truss section is made of cross-linked polymer composite material with carbon fibers. The objective of the tests is to confirm the possibility of creating a lightweight mesh construction using a carbon fiber reinforced polymer composite material. To achieve this goal, the authors were assigned the following tasks: selection of carbon filler of polymer composite materials (PCM); selection of PCM binder; determination of the degree of carbon fiber reinforcement; choice of the number and orientation paths of spiral ribs, number of ring ribs and the sizes of individual ribs. As a result of the research, the calculated indicators for ensuring the bearing capacity and stiffness under the application of axial compressive load were obtained. At the same time, with the determination of bearing capacity, the deformation characteristics of the structure were twice determined in order to confirm their repeatability, as well as linear nature of the dependence of axial and radial deformations as a result of the applied load.

Analysis of the Structure of Cellulose Fibers Using the Imagej Program and Fibercement Properties on their Basis

2020 ◽  
Vol 992 ◽  
pp. 259-264
Author(s):  
A.E. Mestnikov ◽  
V.I. Fedorov
Keyword(s):  
Experimental Study ◽  
Visual Analysis ◽  
Cellulose Fiber ◽  
High Strength ◽  
Cellulose Fibers ◽  
Morphometric Parameters ◽  
Waste Paper ◽  
Cement Stone ◽  
Recycled Paper ◽  
Cellulosic Fibers

This article presents the results of an experimental study of the effect of morphometric parameters of secondary cellulose fiber from various brands of waste paper on the strength characteristics of cement stone. The article is based on the results of determining the morphometric parameters of cellulose fibers. Visual analysis of microphotographs of cellulosic fibers showed that the smallest fractions of fibers were obtained from newspaper waste paper of grade MS-8V. A causal relationship has been established between the fiber content and the strength of an incident stone. It was found that samples with a content of cellulose fibers of 0.5-0.75% of the mass of cement have high strength. The most durable were samples with the addition of cellulosic fibers based on newspaper recycled paper MS-8V.

scholarly journals Short Communication: Biodegradable of bio-composites made from Polylactid Acid (PLA) and cellulose fibers from oil palm empty fruit bunch

2019 ◽  
Vol 11 (1) ◽  
pp. 8-11
Author(s):  
YULIATI INDRAYANI ◽  
LISMAN SURYANEGARA ◽  
SAERI SAGIMAN ◽  
EMI ROSLINDA ◽  
MARWANTO MARWANTO
Keyword(s):  
Polymer Composites ◽  
Polylactic Acid ◽  
Polymer Composite ◽  
Oil Palm ◽  
Short Communication ◽  
Environmental Concern ◽  
Cellulose Fiber ◽  
Cellulose Fibers ◽  
Empty Fruit Bunch ◽  
Empty Fruit Bunches

Indrayani Y, Suryanegara L, Sagiman S,, Roslinda E, Marwanto. 2019. Short Communication: Biodegradable of bio-composites made from Polylactic Acid (PLA) and cellulose fibers from oil palm empty fruit bunch. Nusantara Bioscience 11: 8-11. Over the last two decades, plastic has become an integral part of people's everyday life. However, plastic is a material that difficult to be degraded in the environment. Due to environmental concern, it is indispensable to find environmentally friendly plastic materials. This study aimed to determine the biodegradable polymer composites manufacture from cellulose fibers of oil palm empty fruit bunches (OPEFB) and polylactic acid (PLA). Cellulose fibers from oil palm OPEFB were isolated by chemical methods. Polymer composites made by mixing cellulose fiber of oil palm OPEFB and PLA based on differences in the composition of the cellulose fiber of OPEFB. The composition used is 0 PHR, 5 PHR, 10 PHR, 15 PHR, and 20 PHR. Results showed that polymer composite with higher composition of cellulose fiber of OPEFB more easily degraded in the environment. There are no significant differences in biodegradable between 15 PHR and 20 PHR, neither among 10 PHR, 5 PHR and control. At higher cellulose fiber of OPEFB content, 20 PHR, polymer composite was the most degraded in the environment.

Experimental study of the functional and mechanical properties of shape memory polymer composites for a reflector of the space antenna

2020 ◽  
Vol 86 (1) ◽  
pp. 51-56
Author(s):  
Egor V. Moskvichev ◽  
Alexey Yu. Larichkin
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Shape Memory ◽  
Polymer Composite ◽  
Shape Recovery ◽  
Shape Memory Polymer ◽  
Experimental Tests ◽  
Polymer Composite Material ◽  
Operating Conditions ◽  
Space Antenna

Experimental study of the shape memory polymer composite is carried out as a part of scientific and technological work aimed at development of the new promising reflectors for space antenna. The studied material consists of three-layered carbon biaxial fabric St 12073 impregnated with a polyurethane-based Diaplex MP5510 polymer matrix. This material is intended for manufacturing a frame used in the construction of a precise composite reflector of space antenna. When opening the reflector to the transport position, the rim activated by heating recovers a previously specified shape thus increasing the rigidity of the reflector at the periphery and enhancing the accuracy of the reflecting surface. To study the functional and mechanical properties of the rim material in manufacturing and operating conditions, experimental tests were carried out on the samples with different schemes of reinforcement: [03], [0/±60] and [0/±45]. The main goal of the study is to determine the degree and rate of the shape recovery, reinforcement angles, deformation rate and exposure time in the strained state. The developed test program included several stages. At the first stages, tests were carried out for fixing and restoring the shape upon three-point bending of flat samples at a strain rate of 1, 5, and 10 mm/sec and exposure of the specimens in deformed state for 24, 48, and 96 h. According to the results the material with the reinforcement angles [03] was accepted as optimal for the rim design, as it has maximal shape recovery parameters. For the selected material at the final stage of the study, the elastic modulus and tensile strength were determined at operating temperatures –50, +20, and +60°C. The tests showed that the studied polymer composite material has the desired shape memory properties and is promising for the rim manufacturing provided the heat insulation during operation.

scholarly journals Identification of acoustic emission sources under cyclic loading of the polymer composite material used in shipbuilding

2021 ◽  
pp. 28-33
Author(s):  
О.В. Башков ◽  
А.А. Брянский ◽  
Т.И. Башкова
Keyword(s):  
Acoustic Emission ◽  
Composite Material ◽  
Polymer Composite ◽  
Mechanical Test ◽  
Fatigue Loading ◽  
Polymer Composite Material ◽  
Second Stage ◽  
Kohonen Map ◽  
Ae Signals ◽  
Critical Intensity

Данная работа посвящена исследованию механизмов накопления повреждений в полимерном композиционном материале (ПКМ) в ходе усталостного нагружения. Механическое испытание образца стеклопластика проводили циклическим растяжением в сопровождении регистрации акустической эмиссии (АЭ). Для зарегистрированных сигналов АЭ рассчитывались спектры Фурье и использовались для кластеризации самоорганизующейся картой Кохонена (SOM). Полученные центроиды, для снижения количества анализируемых кластеров, разделяли на кластеры методом k-средних. Кластеры второго этапа кластеризации соотносились с типами повреждений в структуре ПКМ. Рассчитывались периоды критической интенсивности регистрации различных типов образующихся повреждений. Дополнительно проведён анализ пиковых частот уровней вейвлет декомпозиции Добеши 14 сигналов АЭ. На основании проведенных методов анализа данных АЭ описаны протекающие процессы разрушения в образце ПКМ. This work is aimed the study the mechanisms of damage accumulation in a polymer composite material (PCM) during fatigue loading. Mechanical test of a fiberglass sample was done by cyclic tension with acoustic emission (AE) registration. The Fourier spectra were calculated for the recorded AE signals and used for clustering with a self-organizing Kohonen map (SOM). The obtained centroids, in order to reduce the number of analyzed clusters, were divided into clusters by the k-means method. Clusters of the second stage clustering correlated with the types of damage in the structure of the PCM. The periods of the critical intensity of registration of various types of formed damages were calculated. Additionally, the peak frequencies of the levels of Daubechies 14 wavelet decomposition of AE signals was analyzed. Based on the methods for analyzing the AE data, the processes of destruction in the PCM sample are described.

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