Polylactic acid and electron beam radiation modifying method for copolymer composite material thereof

A technology of polylactic acid copolymer and electron beam irradiation, applied in the field of modification of polylactic acid and its copolymer, can solve the problems of difficult to satisfy mechanical properties, expensive synthesis cost, reduced tensile strength, etc., and achieve excellent mechanical properties and cost. Reduced, good biodegradability

Inactive Publication Date: 2008-07-23
SICHUAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Polylactic acid and its copolymers are important biodegradable materials, which are mainly obtained by ring-opening polymerization of lactide (the tensile strength of polylactic acid is generally about 50MPa, and the elongation at break is about 4%; due to plasticization or With the addition of hydrophilic components, the tensile strength of the copolymer will be greatly reduced), but the purification of lactide requires a large amount of organic solvent recrystallization, resulting in expensive synthesis (generally used as a polylactic acid masterbatch for plastics) The price of polylactic acid and its copolymers used as medicine is as high as hundreds of thousands per kilogram)
It is an effective method to reduce costs by using low-priced fillers and polylactic acid and its copolymers to form composite materials, while maintaining the degradation of polylactic acid and its copolymer composites, but the disadvantage is that the mechanics The performance is difficult to meet the requirements of engineering plastics or general-purpose plastics
G.H Yew et al. reported that the composite material formed by polylactic acid and starch has good biodegradability and water absorption, but its mechanical properties decrease with the increase of starch content, and the tensile strength of polylactic acid without starch is 57.8MPa , the elongation at break is 3.8%; while the tensile strength of polylactic acid added with 50% starch is 30.6MPa, the elongation at break is only 1.7% (Polymer Degradation and Stability 2005; 90:488-500)

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] (1) Ingredients

[0022] The mass ratio of starch to polylactic acid is 50:100, the mass ratio of triallyl cyanurate to polylactic acid is 0.5:100, and the tensile strength and elongation at break of polylactic acid are 46MPa and 8% respectively;

[0023] (2) Mix polylactic acid, starch and triallyl cyanurate uniformly with a high-speed mixer at room temperature (25°C) to form a composite material, and then use a film blowing machine at 140°C to form a film product. The tensile strength of the composite material is Tensile strength and elongation at break are 25MPa and 7% respectively;

[0024] (3) Nitrogen discharge the air in the irradiation room of the electron beam equipment, when the oxygen concentration in the irradiation room was 5mg / L, start the electron beam equipment, send the film prepared in step (2) into the irradiation room of the electron beam equipment, close the irradiation room, irradiated with electron beams at room temperature (25° C.), with a radia...

Embodiment 2

[0026] (1) Ingredients

[0027] The mass ratio of starch to polylactic acid-polyethylene glycol copolymer is 20:100, the mass ratio of triallyl pentaerythritol to polylactic acid-polyethylene glycol copolymer is 1:100, polylactic acid-polyethylene glycol copolymer The tensile strength and elongation at break of the product are 18MPa and 160% respectively;

[0028] (2) Mix polylactic acid-polyethylene glycol copolymer, starch and triallyl pentaerythritol uniformly with a high-speed mixer at room temperature (25°C) to form a composite material, and then use a blown film machine at 105°C to form a film product. The tensile strength and elongation at break of the composite material are 11MPa and 130% respectively;

[0029] (3) Nitrogen discharge the air in the irradiation room of the electron beam equipment, when the oxygen concentration in the irradiation room was 10mg / L, start the electron beam equipment, send the film prepared in step (2) into the irradiation room of the elect...

Embodiment 3

[0031] (1) Ingredients

[0032] The mass ratio of silicon dioxide and poly(lactic-co-glycolic acid) copolymer is 10:100, the mass ratio of tetraallyl pentaerythritol and poly(lactic-co-glycolic acid) copolymer is 2:100; the stretching of poly(lactic-co-glycolic acid) Strength and elongation at break are 30MPa and 46% respectively;

[0033](2) At room temperature (25°C), use a high-speed mixer to mix polylactic acid-glycolic acid copolymer, silicon dioxide, and tetraallyl pentaerythritol to form a composite material, and then use a blown film machine at 110°C to form a film product. The tensile strength and elongation at break of the composite material are 32MPa and 32%, respectively;

[0034] (3) Nitrogen discharge the air in the irradiation room of the electron beam equipment, when the oxygen concentration in the irradiation room was 8mg / L, start the electron beam equipment, send the thin film prepared in step (2) into the irradiation room of the electron beam equipment, clo...

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Abstract

The invention relates to a modification method of the electron beam radiation for polylactic acid and the copolymer composite of polylactic acid, which comprises: firstly, the polylactic acid or the copolymer of polylactic acid, the fillers and the cross-bonding agent are mixed homogenously at the ambient temperature to prepare the composite; secondly, the composite is processed to a product which is put in nitrogen or vacuum environment; at last, the product is radiated by an electron beam and the radiation dose is 10 to 180kGy. The ratio of the fillers and the polylactic acid or the ratio of the fillers and the copolymer of polylactic acid is 5:100 to 60:100; the ratio of the cross-bonding agent and the polylactic acid or the ratio of the cross-bonding agent and the copolymer of polylactic acid is 0.5:100 to 10:100.

Description

technical field [0001] The invention belongs to the field of modification methods of polylactic acid and its copolymers, in particular to a method for modifying polylactic acid and its copolymers through compounding and electron beam radiation. Background technique [0002] Polylactic acid and its copolymers are important biodegradable materials, which are mainly obtained by ring-opening polymerization of lactide (the tensile strength of polylactic acid is generally about 50MPa, and the elongation at break is about 4%; due to plasticization or With the addition of hydrophilic components, the tensile strength of the copolymer will be greatly reduced), but the purification of lactide requires a large amount of organic solvent recrystallization, resulting in expensive synthesis (generally used as a polylactic acid masterbatch for plastics) The price of polylactic acid and its copolymer used as medicine is as high as hundreds of thousands per kilogram)....

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08L67/04C08J7/18C08K5/3492B29C71/04C08L3/02C08L1/02C08K3/00
CPCC08J7/123C08J2367/04
Inventor 杨刚缪培凯唐文睿曾科唐艳周柯王宜鹏周鸿飞刘韬赵春娥徐国亮周韶鸿洪海兵
Owner SICHUAN UNIV
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