Effect of Stereoscopic Composite Crystals on Foaming Behavior of PLA

doi:10.19491/j.issn.1001-9278.2021.08.017

Abstract

Abstract:

This paper focused on the effects of stereoscopic composite （Sc） crystals induced by PDLA on the popularity and foaming behavior of the PLLA/PDLA blends. Polytetrafluoroethylene （PTFE） was introduced into the blends as a synergist. The effect of PTFE on the formation of Sc crystals was investigated， and the rheological and foaming behaviors of the blends were also studied. The results indicated that the content of Sc crystals was significantly increased when 0.5 wt.% PTFE was incorporated. The formation of Sc crystals improved the melt strength， promotes the cell nucleation of the blends. This effectively improved the foaming performance of PLA， resulting in the formation of the micro/nano?sized composite cells.

Key words: poly（lactic acid）, stereoscopic composite crystal, foaming

CLC Number:

TQ 321

TANG Yujing, WANG Yaqiao, NI Jingyue, WANG Conglong, WANG Xiangdong. Effect of Stereoscopic Composite Crystals on Foaming Behavior of PLA[J]. China Plastics, 2021, 35(8): 117-124.

Figures/Tables 14

References 20

1	LACTATES.Studies Conducted at Zhejiang University on Lactates Recently Reported ［Stereocomplex Crystallization of High⁃molecular⁃weight Poly（L⁃lactic acid）/Poly（D⁃lactic acid） Racemic Blends Promoted by a Selective Nucleator］［J］. Chemicals & Chemistry，2015，144⁃153.
2	VISCO A， NOCITA D， GIAMPORCARO A， et al. Effect of Ethyl Ester L⁃Lysine Triisocyanate Addition to Produce Reactive PLA/PCL Bio⁃polyester Blends for Biomedical Applications［J］. Journal of the Mechanical Behavior of Biomedical Materials， 2017， 68：308⁃317.
3	邹祎祎，王克俭.可降解泡沫在运输包装领域应用研究进展［J］.塑料包装，2021，31（01）：6⁃9，5.
	ZOU W W， WANG K J.Research Progress in Application of Degradable Foam in Transport Packaging ［J］.Plastic Packaging，，2021，31（01）：6⁃9，5.
4	FIORE A，PARK S，VOLPE S，et al. Active Packaging Based on PLA and Chitosan⁃caseinate Enriched Rosemary Essential Oil Coating for Fresh Minced Chicken Breast Application［J］. Food Packaging and Shelf Life，2021，29.
5	BORKOTOKY S S，DHAR P，KATIYAR V. Biodegradable Poly （lactic acid）/Cellulose Nanocrystals （CNCs） Composite Microcellular Foam： Effect of Nanofillers on Foam Cellular Morphology， Thermal and Wettability Behavior［J］. International Journal of Biological Macromolecules，2018，106.
6	STEFANO G，RICCARDO R，MINNA H，et al. Cellulose Nanofibrils as Reinforcing Agents for PLA⁃based Nanocomposites： An In Situ Approach［J］. Composites Science and Technology，2018，12，015.
7	TSUJI H，TEZUKA Y. Stereocomplex Formation Between Enantiomeric Poly（lactic acid）s. 12. Spherulite Growth of Low⁃molecular⁃weight Poly（lactic acid）s from the Melt［J］. Biomacromolecules，2004，5（4）.
8	JING Z X，SHI X T，ZHANG G C，et al. Formation， Structure and Promoting Crystallization Capacity of Stereocomplex Crystallite Network in the Poly（lactide） Blends Based on Linear PLLA and PDLA with Different Structures［J］. Polymer，2016，92.
9	谢青，包建娜，余承涛，等.高分子立构复合结晶的研究进展［J］.高分子学报，2017（06）：893⁃905.
	XIE Q， BAO J N， YU C T， et al. Research Progress in Stereoscopic Composite Crystallization Of Polymers［J］. Journal of Polymer，2017（06）：893⁃905.
10	ZHANG J ， SATO H ， TSUJI H ， et al. Infrared Spectroscopic Study of CH₃···OC Interaction during Poly（l⁃lactide）/Poly（d⁃lactide） Stereocomplex Formation［J］. Macromolecules， 2017， 38（5）.
11	PAN P J， BAO J N，HAN L L，et al. Stereocomplexation of High⁃molecular⁃weight Enantiomeric Poly（lactic acid）s Enhanced by Miscible Polymer Blending with Hydrogen Bond Interactions［J］. Polymer，2016，98.
12	RIGUERA R ， FREIRE F ， LEIRAS S ， et al. Reversible Assembly of Enantiomeric Helical Polymers： From Fibers to Gels［J］. Chemical Science， 2014， 6（1）.
13	AZZAM T ， ELIYAHU H ， SHAPIRA L ， et al. PolysaccharideOligoamine Based Conjugates for Gene Delivery［J］. Journal of Medicinal Chemistry， 2002， 45（9）：1817.
14	CHEN P， WANG W， WANG Y， et al. Crystallization⁃induced Microcellular Foaming of Poly （lactic acid） with High Volume Expansion Ratio［J］. Polymer Degradation and Stability， 2018， 144： 231–240.
15	Eindhoven University of Technology Details Findings in Chemistry Engineering ［Superior Performance of Fully Biobased Poly（lactide） via Stereocomplexation⁃Induced Phase Separation： Structure versus Property］［J］. Journal of Engineering，2015， 3（7）：1 470–1 478.
16	SCHMIDT S C， HILLMYER M A. Polylactide Stereocomplex Crystallites as Nucleating Agents for Isotactic Polylactide［J］. Journal of Polymer Science Part B， 2001， 39（3）：300⁃313.
17	VERT M，SCHWARCH G，COUDANE J. Polylactide Stereocomplex Crystallites as Nucleating Agents for Isotactic Polylactide［J］.Polymer Physics， 1995， 32：787.
18	ZOU G， QU X， ZHAO C， et al. Self⁃Nucleation Efficiency of PDLA in PLAs： Crystallization Behavior and Morphology［J］. Polymer Science， 2018， 60（2）：206⁃214.
19	赵幸一. PCL/PLA共混材料的流变性能及其对微发泡材料泡孔形态的影响［D］.郑州：郑州大学，2020.
20	倪敬越，余科松，唐娅娥，等.聚乳酸微纳复合泡孔的结构与性能研究［J］.中国塑料，2020，34（04）：20⁃24.
	NI J Y， YU K S， TANG Y E， et al.Study on the Structure and Properties of Poly （lactic acid） Micro Nano Composite Cell［J］.China Plastics， 34（04）：20⁃24.

样品编号	PLLA/份	PDLA/份	CE/份
CE5/PLLA	100	0	5
CE5/PLLA/PDLA5	95	5	5
CE5/PLLA/PDLA10	90	10	5
CE5/PLLA/PDLA15	85	15	5
CE5/PLLA/PDLA20	80	20	5

样品编号	PLLA/份	PDLA/份	CE/份
CE5/PLLA	100	0	5
CE5/PLLA/PDLA5	95	5	5
CE5/PLLA/PDLA10	90	10	5
CE5/PLLA/PDLA15	85	15	5
CE5/PLLA/PDLA20	80	20	5

样品编号	PLLA/份	PDLA/份	CE/份	PTFE/份
CE5/PLLA/PDLA15/PTFE0.25	85	15	5	0.25
CE5/PLLA/PDLA15/PTFE0.5	85	10	5	0.50
CE5/PLLA/PDLA15/PTFE0.75	85	15	5	0.75
CE5/PLLA/PDLA15/PTFE1	85	15	5	1.00

样品编号	PLLA/份	PDLA/份	CE/份	PTFE/份
CE5/PLLA/PDLA15/PTFE0.25	85	15	5	0.25
CE5/PLLA/PDLA15/PTFE0.5	85	10	5	0.50
CE5/PLLA/PDLA15/PTFE0.75	85	15	5	0.75
CE5/PLLA/PDLA15/PTFE1	85	15	5	1.00

样品	Sc晶熔融温度/℃	熔融焓/ J?g^-1	Sc结晶度/ %
PLLA/CE5	-	-	0
PLLA/CE5/PDLA5	214.72	5.71	6.4
PLLA/CE5/PDLA10	213.63	15.25	18.1
PLLA/CE5/PDLA15	222.89	19.13	24.0
PLLA/CE5/PDLA20	225.19	25.89	34.5