scholarly journals Thermal degradation of polypropylene reprocessed in a co-rotating twin-screw extruder: kinetic model and relationship between Melt Flow Index and Molecular weight

2021 ◽  
Vol 20 (2) ◽  
pp. 1079-1091
Author(s):  
L. Martínez-Jothar ◽  
◽  
I. Montes-Zavala ◽  
N. Rivera-García ◽  
Y. Díaz-Ceja ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Kinetic Model ◽  
Thermal Degradation ◽  
Melt Flow Index ◽  
Flow Index ◽  
Twin Screw Extruder ◽  
Melt Flow ◽  
Screw Extruder ◽  
Twin Screw

scholarly journals Synergistic toughening of polypropylene with ultra-high molecular weight polyethylene and elastomer-olefin block copolymers

RSC Advances ◽  
2019 ◽  
Vol 9 (41) ◽  
pp. 23994-24002 ◽  
Author(s):  
Lucheng Qi ◽  
Lei Wu ◽  
Ren He ◽  
Hui Cheng ◽  
Boping Liu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Block Copolymers ◽  
Rheological Properties ◽  
High Molecular Weight ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Twin Screw ◽  
Ultra High Molecular Weight

Blends of polypropylene (PP) and ultra-high molecular weight polyethylene (UHMWPE) with elastomer-olefin block copolymers (OBC) were prepared using an ultrasonic twin-screw extruder, and their mechanical and rheological properties were investigated.

Tuning of HDPE Properties for 3D Printing

2018 ◽  
Vol 773 ◽  
pp. 67-71 ◽  
Author(s):  
Paweesinee Chatkunakasem ◽  
Panisa Luangjuntawong ◽  
Aphiwat Pongwisuthiruchte ◽  
Chuanchom Aumnate ◽  
Pranut Potiyaraj
Keyword(s):  
3D Printing ◽  
Melt Flow Index ◽  
Flow Index ◽  
Melt Blending ◽  
X Ray Diffraction ◽  
Screw Extruder ◽  
Scanning Calorimetry ◽  
Crystalline Polymers ◽  
Twin Screw ◽  
Low Crystalline

The objective of this study is to improve high density polyethylene (HDPE) properties for 3D printing by addition of graphene and low density polyethylene (LDPE). Graphene was prepared by modified Hummer’s method. The prepared graphene was characterized by the infrared spectroscopy and the X-ray diffraction analysis (XRD). Graphene/HDPE and LDPE/HDPE composites were successfully prepared through the melt-blending technique using a twin-screw extruder. The melt flow index (MFI) and differential scanning calorimetry (DSC) were employed to characterize neat HDPE and the modified HDPE. FTIR and XRD results show that graphite was successfully changed into graphene completely and MFI of graphene/HDPE and LDPE/HDPE decreased as the amount of graphene and LDPE in the composite blends increased. DSC results show that the addition of low crystalline polymers can reduce a crystallization temperature and crystallinity content.

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.

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