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A kind of method of promoting polylactic acid stereocomplex crystallization

A technology of stereocomplex crystallization and polylactic acid, which is applied in the field of polymer materials and can solve problems such as unfavorable industrialization and complicated process routes

Active Publication Date: 2022-03-22
SHANDONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Chinese patent (Application No. 201510796830.4) introduces 2-ureido-4[1H]-pyrimidinone (UPy) groups capable of forming quadruple hydrogen bonds at the molecular chain ends of PLLA and PDLA through chemical reactions, although it improves the stereocomposition The content of crystals, but the process route of this chemical modification is relatively complicated, which is not conducive to industrialization
However, there has been no report on the use of halloysite to promote polylactic acid crystallization to form stereocomplex crystals.

Method used

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  • A kind of method of promoting polylactic acid stereocomplex crystallization
  • A kind of method of promoting polylactic acid stereocomplex crystallization
  • A kind of method of promoting polylactic acid stereocomplex crystallization

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Embodiment 1 (adopting the second method)

[0039] Dissolve PLLA / PDLA in chloroform at room temperature according to the weight ratio of 7:3, add 3wt% HNT and ultrasonically disperse for 30min, remove the solvent to obtain a composite material of PLLA / PDLA / HNT; °C for 5 minutes, then cooled to 120 °C at a rate of 150 °C / min for isothermal crystallization for different times to obtain polylactic acid after crystallization. Continue to use DSC detection, heat at a heating rate of 10°C / min, and record the melting curve, as shown in Figure 1.

[0040] Using a vulcanizing machine, the composite material of PLLA / PDLA / HNT was melted and molded into thin sheets at 250°C, and quickly placed in an oven at 120°C for isothermal crystallization for 1 hour to obtain polylactic acid after crystallization; XRD detection was carried out, and the results were as follows figure 2 Shown; DMA is used to detect dynamic mechanical properties, and the results are as follows image 3 .

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Embodiment 2

[0046] Embodiment 2 (adopting the first method)

[0047] Dissolve PLLA and PDLA in chloroform at room temperature according to the weight ratio of 9:1, add 1wt% HNT and ultrasonically disperse for 30 minutes to obtain a uniform mixed solution; cast the mixed solution in a polytetrafluoroethylene mold, and let the solvent Evaporate to obtain a film sample containing stereocomplex crystals. The melting behavior was detected by DSC, and the dynamic modulus at 100 °C was detected by DMA. The results are shown in Table 1.

Embodiment 3

[0048] Embodiment 3 (adopting the first method)

[0049] Dissolve PLLA / PDLA in chloroform at room temperature according to the weight ratio of 9:1, add 1 wt% of HNT modified by silane coupling agent KH550, and disperse ultrasonically for 30 minutes to obtain a uniform mixed solution; cast the mixed solution on polytetrafluoroethylene In the mold, the solvent was evaporated at 70°C to obtain a film sample containing stereocomplex crystals. The melting behavior was detected by DSC, and the dynamic modulus at 100 °C was detected by DMA. The results are shown in Table 1.

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Abstract

The invention discloses a method for promoting stereocomplex crystallization of polylactic acid, which comprises dissolving L-polylactic acid, D-polylactic acid, nano halloysite or modified nano halloysite in an organic solvent to disperse evenly, and controlling the temperature to remove the solvent Or melt and recrystallize after removing the solvent to obtain polylactic acid containing a stereocomplex crystal structure. The present invention skillfully utilizes the structural matching of polylactic acid stereocomplex crystals and nano halloysite crystals to induce stereocomplex crystals, forming a good lattice matching effect, thereby preferentially promoting the formation of polylactic acid stereocomplex crystals. grow.

Description

technical field [0001] The invention belongs to polymer materials, and in particular relates to a method for increasing the content of polylactic acid stereocomplex and material performance by adding nano halloysite. Background technique [0002] At present, in the face of the increasing environmental crisis, it is particularly urgent to vigorously develop and promote the application of biodegradable polymer materials. Polylactic acid (PLA) uses biofermented lactic acid as the raw material, has good biocompatibility and biodegradability, and has processing properties comparable to polyolefins, so it has become the most valuable biodegradable polymer species for popularization and application. However, the slow crystallization rate of polylactic acid leads to very low crystallinity of usually melt-processed products, which causes thermal deformation of products near the glass transition temperature (55°C), which greatly limits the application of polylactic acid. [0003] In ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08L67/04C08K7/26C08K9/06
CPCC08L67/04C08L2205/025C08K2201/011C08L2201/08C08K7/26C08K9/06
Inventor 赵丽芬田阳田秀娟魏亚菲付振江
Owner SHANDONG UNIV OF SCI & TECH