Hemp Fibre

Describe the Harvesting and Retting Process of Hemp Fibre

Harvesting: Hemp plants are typically harvested 70–90 days after planting, when the male plants begin to shed pollen. Harvesting can be done manually or mechanically. The stalks are cut close to the ground and left in the field for further processing.
Retting: This is a crucial step to separate the bast fibres from the woody core (hurd). There are several retting methods:
- Dew Retting: The stalks are left in the field to be broken down naturally by dew and microbes.
- Water Retting: Involves soaking the stalks in ponds or tanks to promote microbial decomposition.
- Enzymatic Retting: Uses controlled enzymes to expedite fibre separation.
- Chemical Retting: Involves chemicals (e.g., sodium hydroxide) to speed up the retting process, though it may impact fibre quality and sustainability.

Classify Hemp Fibre

Primary (Long) Fibre: Also called bast fibre, extracted from the outer layer of the stalk. It is strong, long, and used in high-quality applications like textiles and composites.
Secondary (Short) Fibre: Comes from the inner core or as a by-product during processing. It is shorter, coarser, and used in products like insulation, paper, and composites.

Mention the Chemical Composition of Hemp Fibre

Describe the Physical & Chemical Properties of Hemp Fibre

Physical Properties:
- Light to dark brown colour
- High tensile strength and durability
- Coarse texture with moderate softness when refined
- Excellent moisture-wicking and breathability
- Biodegradable and sustainable
Chemical Properties:
- Resistant to saltwater and UV degradation
- High cellulose content makes it chemically reactive like other bast fibres
- Alkali-resistant; sensitive to strong acids
- Can be dyed and finished with standard textile chemicals

Mention the End Uses of Hemp Fibre

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