Biodegradable starch composite materials and their preparation methods

Abstract

This invention provides a biodegradable starch composite material and its preparation method. The biodegradable starch composite material has a tensile strength greater than or equal to 10 kg / cm² and a melt flow index greater than or equal to 1 g / 10 min at 190°C under a 2.16 kg load. The biodegradable starch composite material of this invention possesses high tensile strength and a high melt flow index, and its excellent mechanical properties and processability are beneficial for manufacturing high-performance biodegradable downstream products.

Claims

1. A biodegradable starch composite material, comprising 60 to 80 parts by weight of starch, 5 to 10 parts by weight of plant fiber, 5 to 20 parts by weight of biodegradable resin, 0.3 to 5 parts by weight of modifier, and 0.3 to 3 parts by weight of plasticizer; wherein, The biodegradable starch composite material has a tensile strength greater than or equal to 10 kg / cm², as measured according to the ASTM D638 standard method. The biodegradable starch composite material has a melt flow index greater than or equal to 1 g / 10 min, as measured according to the ASTM D1238 standard method at 190°C and under a load of 2.16 kg.

2. The biodegradable starch composite material as claimed in claim 1, wherein the average particle size of the starch in the biodegradable starch composite material is from 0.5 micrometers to 18 micrometers.

3. The biodegradable starch composite material as claimed in claim 1, wherein the length of the plant fiber is from 0.1 mm to 30 mm.

4. The biodegradable starch composite material as claimed in claim 1, wherein the starch comprises cereal starch, root starch, legume starch, or a combination thereof.

5. The biodegradable starch composite material as claimed in claim 1, wherein the plant fiber comprises lignocellulose, leaf fiber, bast fiber, seed fiber, or a combination thereof.

6. The biodegradable starch composite material as described in claim 1, wherein, Based on the total weight of the biodegradable starch composite material, the total amount of starch and plant fiber used is 70% to 86% by weight.

7. The biodegradable starch composite material as claimed in claim 1, wherein the biodegradable resin comprises polybutylene succinate, adipic acid-butylene terephthalate copolymer, polycaprolactone, polyhydroxyalkanoate, polybutylene succinate, or a combination thereof.

8. The biodegradable starch composite material as claimed in claim 1, wherein the modifier comprises an epoxy resin, a maleic anhydride copolymer, a silane compound, a carbonate compound, or a combination thereof, the modifier contains three or more functional groups, and the weight average molecular weight of the modifier is greater than 1500 g / mole.

9. The biodegradable starch composite material as claimed in claim 1, wherein the plasticizer comprises vegetable oil, citrate derivatives, or a combination thereof.

10. A method for manufacturing a biodegradable starch composite material as described in any one of claims 1 to 9, comprising the steps of: providing a dried starch having a moisture content of less than 3%; mixing the dried starch, a plant fiber, a biodegradable resin, a modifier, and a plasticizer to obtain a starch mixture comprising 60 to 80 parts by weight of starch, 5 to 10 parts by weight of plant fiber, 5 to 20 parts by weight of biodegradable resin, 0.3 to 5 parts by weight of modifier, and 0.3 to 3 parts by weight of plasticizer; and kneading, extruding, granulating, and drying the starch mixture to obtain the biodegradable starch composite material.

11. The method as described in claim 10, wherein, The starch mixture is fed into an extruder for mixing, the extruder having 3 to 8 screws.

12. The method as described in claim 10, wherein, The starch mixture is kneaded at 120°C to 200°C for less than 3 minutes.

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