Preparation method of reinforced and toughened polylactic acid

A technology of strengthening and toughening polylactic acid, which is applied in the processing field of polymer materials, can solve the problems of strength reduction, toughness reduction, strength and rigidity reduction, etc., and achieve the effect of weakening the strength difference, increasing the crystallization speed, and benefiting the toughness

Active Publication Date: 2016-04-13
SICHUAN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

HuanXu[XuH, ZhongGJ, FuQ.J.ACSApplMaterInterfaces.2012,4(12):6774-6784.] et al prepared polylactic acid and polylactic acid/polyethylene glycol composite materials containing string crystal structure by dynamic pressure-holding injection molding technology , although the strength of the prepared polylactic acid material has increased, but the toughness has decreased; while the toughness of the polylactic acid/polyethylene glycol compos...

Method used

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  • Preparation method of reinforced and toughened polylactic acid
  • Preparation method of reinforced and toughened polylactic acid
  • Preparation method of reinforced and toughened polylactic acid

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Experimental program
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Embodiment 1

[0033] (1) Polylactic acid (PLA2003D, Natureworks, USA) was selected as the experimental material, its melting index was 6g / 10min (210°C, 2.16Kg), and its weight average molecular weight was 1.85×10 5 g / cm 3 , the molecular weight distribution is 1.73. Dry in a vacuum oven at 60°C for 12 hours under vacuum.

[0034] (2) Put the dried pellets into a multi-stage stretching device consisting of an extruder (1), a confluence (2), a force assembly unit (3), and a cooling roller (4) (see figure 1 ) in the extruder. After the division-deformation-stacking action of the force assembly unit, it flows out from the discharge port, and after being cooled by the cooling roller, the polylactic acid material with a width and thickness of 30mm and 1.5mm respectively is obtained.

[0035] Here, the structure of the multistage stretching device will be described first. figure 1 In the process, the discharge port of the extruder is connected to the feed port of the confluence, and the discha...

Embodiment 2

[0038] (1) Polylactic acid (PLA2003D, Natureworks, USA) was selected as the experimental material, its melting index was 6g / 10min (210°C, 2.16Kg), and its weight average molecular weight was 1.85×10 5 g / cm 3 , the molecular weight distribution is 1.73. Dry in a vacuum oven at 60°C for 12 hours under vacuum.

[0039] (2) Put the dried pellets into a multi-stage stretching device consisting of a single-screw extruder (1), a confluence (2), a force assembly unit (3), and a cooling roll (4) (see figure 1 ) in a single-screw extruder. After the division-deformation-stacking action of the force assembly unit, it flows out from the discharge port, and after being cooled by the cooling roller, the polylactic acid material with a width and thickness of 30mm and 1.5mm respectively is obtained. The temperatures of the feeding port, conveying section, melting section, and homogenizing section of single-screw extruder 1 are 125°C, 185°C, 188°C, and 185°C respectively; the temperatures o...

Embodiment 3

[0043] (1) Polylactic acid (PLA2003D, Natureworks, USA) was selected as the experimental material, its melting index was 6g / 10min (210°C, 2.16Kg), and its weight average molecular weight was 1.85×10 5 g / cm 3 , the molecular weight distribution is 1.73. Dry in a vacuum oven at 60°C for 12 hours under vacuum.

[0044] (2) Put the dried pellets into a multi-stage stretching device consisting of a single-screw extruder (1), a confluence (2), a force assembly unit (3), and a cooling roll (4) (see figure 1 ) in a single-screw extruder. After the division-deformation-stacking action of the force assembly unit, it flows out from the discharge port, and after being cooled by the cooling roller, the polylactic acid material with a width and thickness of 30mm and 1.5mm respectively is obtained. The temperatures of the feeding port, conveying section, melting section, and homogenizing section of the single-screw extruder (1) are respectively 125°C, 185°C, 188°C, and 185°C; 185°C.

[...

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Abstract

The invention discloses a preparation method of reinforced and toughened polylactic acid. The preparation method is characterized in that during the processing process, the crystallized morphology of the polylactic acid is controlled so as to improve the mechanical property of the polylactic acid. Particularly, during the processing process, certain shearing force fields and certain bidirectional drawing force fields are applied on a polylactic acid melt in different directions through the control of the number and the type of force assembling units, when the shearing and drawing action force is large enough, polylactic acid molecules are directionally arranged in the force field direction at first to form shish, then polylactic acid lamellar crystals are arranged in a direction perpendicular to the shish, and at least, an shish-kebab crystallization structure is formed; and the sizes of crystalline grains are small, besides, a large amount of interfaces are introduced in a polylactic acid material, so that the strength and the toughness of the polylactic acid material are remarkably improved. The more the number of the force assembling units with higher melt deformation degrees is, the higher the strength of the bidirectional drawing force field in the direction perpendicular to the extrusion direction is, and the smaller the mechanical strength difference of the prepared polylactic acid product in the extrusion direction and the direction perpendicular to the extrusion direction is. The preparation method has the advantages that the force assembling units are additionally arranged on a traditional extrusion device, the preparation method is simple in operation, can be produced continuously, is convenient to control, stable in quality, and high in production efficiency, has a good industrial and market prospect, can be widely applied to the preparation of a polylactic acid plate, a polylactic acid sheet and a polylactic acid film material, with high strength and toughness.

Description

technical field [0001] The invention relates to a method for preparing reinforced and toughened polylactic acid by an extrusion method, and belongs to the technical field of polymer material processing. Background technique [0002] Petroleum-based polymer materials are widely used in our production and life due to their light weight, high strength, and easy processing and molding. However, general polymer materials are difficult to degrade and consume a lot of petroleum resources. In order to solve the problems of white pollution and energy crisis, many studies are devoted to replacing petroleum-based polymer materials with degradable plastics, among which polylactic acid materials are widely studied. Polylactic acid is a biodegradable polymer prepared by chemical synthesis using renewable plant resources as raw materials. It gets rid of the dependence on petroleum resources and can be completely degraded into CO 2 and H 2 O. With its good biocompatibility, excellent str...

Claims

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Application Information

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IPC IPC(8): B29C47/00B29C47/08B29K67/00
CPCB29C48/00B29C48/267B29K2067/046
Inventor 吴宏郭济伟郭少云夏立超李春海
Owner SICHUAN UNIV
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