bast fiber

Also known as: bast fiber layer

Facts (32)

Sources

A critical review of industrial fiber hemp anatomy, agronomic ... bioresources.cnr.ncsu.edu BioResources 32 facts

claimFor high-quality bast fibers, hemp stands should be harvested at technical maturity or before grain production begins.

claimA typical industrial hemp plant is composed of stalks, flowers, leaves, roots, and seeds, with the stalk consisting of a hollow inner core of rigid woody material called hurd surrounded by a layer of long fibers known as bast.

claimTo obtain high-quality bast fiber, hemp growers should target maximum plant height and minimum stem diameter, according to Deng et al. (2019).

claimExcessive sowing density generally decreases bast fiber content and quality, overall biomass yield, grain yield, panicle yield, stalk height and diameter, and partially, cellulose content, according to Burczyk et al. (2009).

claimPhosphorus fertilization affects industrial hemp plant height, tensile strength, and elasticity of bast fibers, but does not affect grain, stem, or biomass yield.

claimHemp biocomposites are limited to processing temperatures below 230 °C to avoid thermal degradation of the bast fibers, making them suitable for polypropylene and polyethylene plastics but unsuitable for polyamides, polyesters, or polycarbonates which require temperatures above 250 °C.

claimDioecious industrial hemp grown for bast fiber is typically harvested when the male plants have finished blooming.

procedureFor high-quality bast fiber applications, industrial hemp stalks are cut into 1-meter sections and aligned parallel, leaving a continuous layer of stalks on the ground before being retted or sent to processing.

claimThe optimal period to harvest industrial hemp for bast fiber is before the grains are completely mature, which is typically 70 to 90 days after sowing.

claimDecortication is the process of separating bast fibers from the hurds of the hemp stalk.

claimHemp hurds are the woody interior portions of the hemp stalk that have been broken down into pieces and separated from the bast fibers, according to Xu et al. (2022).

claimIndustrial hemp bast fiber becomes too coarse for textile applications if harvested later than 70 to 90 days after sowing.

claimHemp hurds are comprised of xylem tissue that is separated from the bast fiber layer by cambium tissues.

claimThe quality and yield of industrial hemp bast fiber are affected more by potassium than by phosphorus.

claimBaling hemp immediately after harvest in a non-parallel orientation results in a significantly lower yield of long bast fibers compared to processing parallel-aligned hemp.

claimIndustrial hemp is considered the second-largest farmed bast fiber after jute, and it serves as a feedstock for fibers, biocomposites, packaging, and bioplastics due to its renewable, biodegradable, and recyclable qualities.

claimOver-retting can result in bast fiber deterioration and decreased fiber strength, while under-retting may produce weak bast fibers and poor bast fiber separation.

procedureHemp hurd, a byproduct of bast fiber generation, can be pyrolyzed and gasified with fir sawdust to produce biochar.

claimWater retting is used to extract long bast fibers that are distinguished by high quality, including fineness, mechanical characteristics, and spinnability, making them suitable for textile applications.

claimRetting is a microbial process that breaks down the chemical bonds between bast fiber bundles and hurds by degrading lignin or pectin, enabling the separation of hurds from the bast fibers.

claimAs hemp plant height increases, stem diameter decreases, which causes the proportion of bast fibers to hurd fibers to increase.

measurementThe yield of bast fiber content derived from unretted hemp stems is approximately 6.5% higher than that derived from retted hemp stems.

measurementBast fiber content in hemp ranges from 14% to 48% of the plant's mass depending on the cultivar, with most fiber varieties containing about 30% bast fiber, according to Ehrensing (1998) and Musio et al. (2018).

claimTo obtain high-quality bast fiber from industrial hemp, the plant should be harvested before grain and cannabinoids begin to develop.

claimBreaking is a bast fiber separation step that uses cylindrical rollers to break down hurds, which partially separates the bast fibers.

claimHarvesting industrial hemp at full bloom results in the maximum yield of bast fiber, cellulose, and overall biomass.

referenceRoy, S., and Lutfar, L. B. (2012) authored 'Bast fibres: Ramie' in the 'Handbook of Natural Fibres', which provides information on ramie as a bast fiber.

claimPotassium uptake in industrial hemp increases with plant maturity, with the highest uptake occurring during the development stage of bast fibers, which causes significant increases in cellulose and hemicellulose content.

claimSecondary macronutrients and micronutrients such as magnesium and calcium have slight effects on industrial hemp plant growth but no direct effect on grain and bast fiber yield, with the exception of boron and copper.

claimThe hurd of an industrial hemp stalk is engirdled by vascular cambium, along with an outer layer of cells made up of epidermal tissue, cortex, and phloem that forms the bark, within which the bast fibers are located.

claimChemical retting is cost-efficient and ensures high yield and high quality of bast fibers.

claimHemp fines are a by-product of the hemp hurd and bast fiber production process, consisting of small particles of hurds mixed with short bast fibers.