How to find density of natural fibers, which are also hydrophobic in nature and micro porous? Also when we use thermoplastic as matrix and natural fiber as reinforcement, the density of fiber may vary due to variation in inter-facial bonding and due to processing conditions. Then which value is to be considered as benchmark?
I agree that a simple Achimedes density determination is probably the way to go. I can't find the reference off hand, but my student used canola oil as the immersion fluid, and as I recall this is well supported in the literature.
I agree with Mr. David A Jesson. You may use Archimedes or Buoyancy method to identify the density. Or use Impedance Tube 2 way microphone (depend on model) also can obtain if you seeking for Bulk Density.
The most accurate method is the pycnometry. Water or gas pycnometery, both are good. In these methods, the porosity of the natural fibers such as lumen voids are not included in the density of the fibers and the obtained value would be the absolute density of the natural fibers. If you use the Archimedes method with water or canola oil, you will get the relative density of the fibers. This means the air in the lumens is included in the density and you will get a lower density compare to the pycnometry method.
Hello Mr. Lilla! If you are using the fibre as reinforcement, I would say that it`s advisable to refer as the density in the composite rather then it before the processing as it might change during the processsing. A very straightforward methodology to determine it is the relationship between the fibre content and the density of the composite, which can be find using a test sample with known dimensions and weight.
For a fiber-reinforced composite it can be possible to indirectly evaluate fiber density by knowing the mass ratio of fiber used to formulate the composite and the densities of the composite and matrix phases. Often, the density of the matrix material can be previously known, and it may be enough to measure the density of the composite. The Archimedes (immersion) method can be adopted for this purpose. Alternatively, for samples with suitable geometric characteristics, the geometric density can be readily accessed. Let us call the mass of fiber, of the matrix, and that of composite, respectively Mf, Mx, and Mc. Let the corresponding volumes be Vf, Vx, and Vc. The mass to volume ratios are densities, denoted as ρf, ρx, and ρc. Accepting volume additivity, i.e. Vx = Vc - Vf, we will have ρf = Mf / (Mc / ρc - Mx / ρx). Here, substitution of Mx = Mc – Mf, from mass balance, yields ρf = R / [1 / ρc - (1 – R) / ρx], where R= Mf / Mc stands for mass ratio concentration (mass of fiber : mass of composite). The obtained equation can be used to evaluate fiber density.
To complement my last answer, I would like to remark that the equation derived above can be alternatively given as a 'mixture rule' for the composite density: 1 / ρc = R / ρf + (1 - R) / ρx. It states that the specific volume (volume/mass) of a fiber-reinforced composite can be estimated as given by the arithmetic mean (weighted by mass fraction) of the specific volumes of its components (fiber and matrix). Obviously, this simple 'mixture rule' does not account for the possible influence of voids.
Please note also that the above given 'mixture rule' could have been alternatively derived in terms of volume fraction of fiber in the composite (f), what would lead directly to the composite density expressed as the arithmetic mean (weighted by volume fraction) of the densities of its components, fiber and matrix: ρc = f·ρf + (1 - f)·ρx.
Characterization of new natural cellulosic fiber from Cissus quadrangularis root. Carbohydrate Polymers, 110 (2014) 423–429
Characterization of new natural cellulosic fiber from Cissus quadrangularis stem, Carbohydrate Polymers,117 (2015) 392–399
Read my article for your answer...
do we have literature on using pycnometer for fiber strands 2-5cm long?
Because of the unique structure, surface morphology and hydrophilic nature of natural fibers, measuring their density is a challenge.
Depending on type accuracy that you are looking for, there are two methods of measurements. 1- gas pycnometry 2-Archimedes method.
1- Gas pycnometry is an acurate method of measurement, but might not be available to you. you can use either Nitrogen or Helium.
2- Archemedes method is simpler and you can do it in any lab set-up which is availabe to you. you can follow the procedure for density measurements usning submersion method. BUT there are differences when deadling with porous materials and especially natural fibers:
2-1) the liquid or the media that you are using is very important in your final results. for Flax fiber either soybean oil, or canola oil is recommended. our experiments and reserach have shown that using mentioned oils will provide the best results comapred to gas pycnometry.
2-2) for better results you have to use vacuume chamber. after measuring dry weight of your fiber, and after submersion, place your container with fiber in it under vacuum pressure for 5-10 minutes ( pressure over -70kPa is recommended).
2-3 make sure that you condition your fiber before doing the measurements. moisture content. usually drying your fiber in the oven for 6-10 hours is recommended.
Please do not hesitate to contact me if you had any questions.
hi,
The low density is one of factors that characterizes the natural fibers over the synthetic ones
the gas pycnometer was used to assess the real density of natural fibers
Regards,
Dear Sir,
Please kindly go through this paper.
https://www.sciencedirect.com/science/article/pii/S0144861718314152
There is a theoretical method that can be used to measure the density of the natural fibre.
Step 1: Study of cross-sectional view of the fibre via scanning electron micrograph that can be used to measure diameter of fibre (d).
Step 2: Determination of linear density of fibre in TEX (weight in g/10^5 cm)
* This method is known as gravimetric method. In this method at first 100 numbers of fibres with 2 mm length of are counted using a magnified glass. A holder with 2 mm gauge length, and sharp blade are required.
* The weight of 100 fibres each of 2 mm length (2X 100= 200 mm) can be measured using electronic balance. The TEX value of the fibre can then be calculated using the weighed mass of 200 mm long fibre mass.
Step 3: For final calculation of fibre density we have to assume that the fibre is cylindrical in shape and is not compressible.
Now we can use the formula for calculation volume of cylindrical shape.
Volume of cylindrical 10 ^ 5 cm long fibre * density (g/cc)= TEX
Thereby, density (g/cc)= TEX /(Volume of cylindrical 10 ^ 5 cm long fibre)
Consult the figure.
There are five test methods:
- the diametral and linear density,
- Archimedes,
- helium pycnometry,
- the gradient column
- liquid pycnometry.
- Badges
- Science topic
- Similar topics
- Biological Science
- Physiology
- Physiological Processes
- Stress