Preparation Of Polyurethane Nanocapsules Based On Reverse Emulsification Method And Its Application In Aromatic Viscose Fibers

Lavender essential oil is a kind of popular fragrance,which has a pleasant fragrance and a variety of pharmacological functions.Polyurethane is a kind of widely used polymer material,which has a wide range of hardness,high elasticity and excellent strength,wear resistance,fatigue resistance,high temperature resistance and shock resistance.Hollow polymer capsules have optical properties,electrical properties and catalytic properties,can encapsulate a variety of guest molecules such as drug enzyme dyestuff nanoparticles,and can control the reaction conditions to release at a certain speed.Using the capsule technology,lavender oil was embedded in the polyurethane shell,which significantly enhanced the durability and thermal stability of lavender oil release.Lavender essential oil is realized its permanent solid after the encapsulation,thus more widely used in the agricultural,food industry,daily chemical and textile fields.On the contrary,Phase inversion emulsification is a kind of low energy emulsification method,which overcomes the disadvantages of high energy emulsification method such as high energy consumption,high cost and poor environmental protection measures,and is more in line with the requirements of batch production.In this theses,a narrow-dispersed nanoemulsion containing lavender essential oil was successfully prepared via phase inversion emulsification.The nanocapsules with lavender essential oil as core material and polyurethane as wall material were successfully synthesized by interfacial polymerization.Then,the nanocapsule slurry was mixed with viscose spinning stock to get the aromatic viscose fiber.The nanoemulsion,nanocapsules and aromatic viscose fibers were measured and characterized by LPSA,SEM,TEM,FTIR,TG,UV spectrophotometer,etc.The results showed that the speed of dripping water,the amount of water and emulsifier and the rate of oil to emulsion all had great impact on the particle size of emulsion.For the micro-nano emulsion system about {[lavender essence oil/TDI trimer solution](1)+[Tween80(21)/Span80(22)]+ water(3)},the optimal ratio of tween80 to Span80 is 0.579:0.421,namely the value of HLB is 10.5.And the optimal ratio of oil to emulsion is 15:8.The conductivity of the emulsion showed a trend of first increase and then decrease with the water increasing,the particle size of emulsion was around 200nm,and the distribution was uniform and presented narrow dispersion.The prepared nanocapsules has uniform particle size and obvious core-shell structure.Its diameter is about 100-600nm,surface is smooth and compact.When the essential oil/TDI trimer ratio is 5:10,the EY was up to 70.7%,the EE and LC were up to 98.6%and 64.8%respectively.And the thermal stability of nanocapsules was great.The structure and thermal stability of aromatic viscose fiber was the same as common viscose fiber.Aromatic viscose fibers' mechanical strength was decreased,and the antistatic property was enhanced.The thermal stability of aromatic viscose fiber whose ratio of containing nanocapsules is 2%was similar to common viscose fiber.The test of aromatic viscose about fragrant properties showed that it had good performance in natural environment.And its fragrance rate was still above 60%after being placed at high temperature for 90 days,what's more,the fragrance rate of fiber had a minimum of 2%after washing 20 times.And the fragrance rate of fiber was positively correlated with the dosage of nanocapsules.