scholarly journals Investigation of the Thermal and Hydrolytic Degradation of Polylactide during Autoclave Foaming

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2624
Author(s):  
Julia Dreier ◽  
Christian Brütting ◽  
Holger Ruckdäschel ◽  
Volker Altstädt ◽  
Christian Bonten
Keyword(s):  
Thermal Degradation ◽  
Hydrolytic Degradation ◽  
Reactive Extrusion ◽  
Foaming Properties ◽  
Twin Screw Extruder ◽  
Degradation Behavior ◽  
Screw Extruder ◽  
Melt Strength ◽  
Twin Screw ◽  
Good Potential

Polylactide (PLA) is one of the most important bioplastics worldwide and thus represents a good potential substitute for bead foams made of the fossil-based Polystyrene (PS). However, foaming of PLA comes with a few challenges. One disadvantage of commercially available PLA is its low melt strength and elongation properties, which play an important role in foaming. As a polyester, PLA is also very sensitive to thermal and hydrolytic degradation. Possibilities to overcome these disadvantages can be found in literature, but improving the properties for foaming of PLA as well as the degradation behavior during foaming have not been investigated yet. In this study, reactive extrusion on a twin-screw extruder is used to modify PLA in order to increase the melt strength and to protect it against thermal degradation and hydrolysis. PLA foams are produced in an already known process from the literature and the influence of the modifiers on the properties is estimated. The results show that it is possible to enhance the foaming properties of PLA and to protect it against hydrolysis at the same time.

scholarly journals Properties of Poly(Lactic Acid) Filled with Hydrophobic Cellulose/SiO2 Composites

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Kittithorn Lertphirun ◽  
Kawee Srikulkit
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Hydrolytic Degradation ◽  
Poly Lactic Acid ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Twin Screw ◽  
Hydrolysis Of Cellulose ◽  
One Step ◽  
Hydrolysis Of

Hydrophobic cellulose/SiO2 composites were prepared. Resultant hydrophobic cellulose/SiO2 composites were melt mixed with PLA using a twin-screw extruder to obtain 10 wt% masterbatch. Again, 10 wt% masterbatch was melt mixed with virgin PLA, resulting in PLA containing hydrophobic cellulose/SiO2 at various contents (1 wt%, 3 wt%, and 5 wt%) using a twin-screw extruder (barrel zone temperature: 150/160/170/180/190°C (die zone)). Injection-molded samples were prepared for mechanical properties evaluation. Results showed that poor mechanical properties found at low percent loadings were associated with a significant depolymerization of masterbatch composition due to twice thermal treatments. Note that 10 wt% masterbatch was subjected to injection molding straight away in a one-step process. Results showed that 10 wt% hydrophobic cellulose/SiO2/PLA composites exhibited mechanical properties equivalent to neat PLA. Importantly, the addition of hydrophobic cellulose/SiO2 at high percent loading could favor landfill degradation of PLA via water absorption ability of cellulose. It was expected that enzymatic hydrolysis of cellulose resulted in the formation of lactic acid and silicic acid which consequently catalyzed the hydrolytic degradation (acid hydrolysis) of PLA. The hydrolytic degradation produced carboxylic acid end group which further accelerated the degradation rate.

Graft Polymerization of L-Lactide onto Cellulose in Ionic Liquid via Twin Screw Extruder

2013 ◽  
Vol 658 ◽  
pp. 8-12
Author(s):  
Xuan Zhong ◽  
Xian Tao Tong ◽  
Mu Huo Yu ◽  
Hai Feng Li ◽  
Huan Li ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Ionic Liquid ◽  
Ring Opening ◽  
Graft Polymerization ◽  
Reactive Extrusion ◽  
Extrusion Process ◽  
Twin Screw Extruder ◽  
Reaction Products ◽  
Screw Extruder ◽  
Twin Screw

A twin-screw extruder was used to carry out the ring opening graft polymerization of L-lactide onto cellulose through reactive extrusion process. Ionic liquid (1-butyl-3-methylimidazolium chloride) [Bmim]Cl and Sn(oct)2 were used as solvent and catalyst, respectively. FTIR, TGA and XRD were used to investigate the structure, thermal stability and crystalline behavior of the reaction products. The result showed a successful ring opening polymerization of L-lactide on cellulose. Furthermore, it showed a increased crystalline degree and thermal stability after being introduced the PLLA.

scholarly journals Single-step reactive extrusion of PLLA in a corotating twin-screw extruder promoted by 2-ethylhexanoic acid tin(II) salt and triphenylphosphine

Polymer ◽  
2000 ◽  
Vol 41 (9) ◽  
pp. 3395-3403 ◽  
Author(s):  
S. Jacobsen ◽  
H.G. Fritz ◽  
Ph. Degée ◽  
Ph. Dubois ◽  
R. Jérôme
Keyword(s):  
Reactive Extrusion ◽  
Single Step ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Twin Screw

Effect of Jute Fiber’s Thermal Degradation on the Fiber Strength and its Polymer Composites

2015 ◽  
Vol 1110 ◽  
pp. 7-12
Author(s):  
Takayasu Fujiura ◽  
Ryosuke Nakamura ◽  
Tatsuya Tanaka ◽  
Yoshihiko Arao
Keyword(s):  
Tensile Strength ◽  
Thermal Degradation ◽  
Fiber Strength ◽  
Tensile Tests ◽  
Jute Fiber ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Test Pieces ◽  
Twin Screw ◽  
Molded Sample

In this study, we investigated the effect of jute fiber’s thermal degradation on fiber strength and its polymer composite. First, we conducted a tensile strength test of a single jute fiber. Next, polyethylene and jute fibers were mixed by twin-screw extruder to make pellets. After making pellets, we used injection molding machine to make the test pieces. Tensile tests were conducted using injection molded sample. As a result, in the experiment of the single fibers, tensile strength of jute fiber monotonically decreased with increasing drying temperature. In case of composite, the tensile strength of molded sample increased with increasing control temperature in twin screw extrude in a range between 150°C ~ 220°C. When the temperature of twin-screw extruder was controlled above 300°C, pellets were burned black by thermal degradation and couldn’t fabricate the test piece.

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