scholarly journals How Is Rheology Involved in 3D Printing of Phase-Separated PVC-Acrylate Copolymers Obtained by Free Radical Polymerization

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2070
Author(s):  
Mario Iván Peñas ◽  
Miren Itxaso Calafel ◽  
Roberto Hernández Aguirresarobe ◽  
Manuel Tierno ◽  
José Ignacio Conde ◽  
...  
Keyword(s):  
3D Printing ◽  
Radical Polymerization ◽  
Vinyl Chloride ◽  
Relaxation Modulus ◽  
Continuous Phase ◽  
3D Printer ◽  
Fused Filament Fabrication ◽  
Poly Vinyl Chloride ◽  
Melt Elasticity ◽  
Scanning Electron

New auto-plasticised copolymers of poly(vinyl chloride)-r-(acrylate) and polyvinylchloride, obtained by radical polymerization, are investigated to analyse their capacity to be processed by 3D printing. The specific microstructure of the copolymers gives rise to a phase-separated morphology constituted by poly(vinyl chloride) (PVC) domains dispersed in a continuous phase of acrylate-vinyl chloride copolymer. The analysis of the rheological results allows the suitability of these copolymers to be assessed for use in a screw-driven 3D printer, but not by the fused filament fabrication method. This is due to the high melt elasticity of the copolymers, caused by interfacial tension between phases. A relationship between the relaxation modulus of the copolymers and the interlayer adhesion is established. Under adequate 3D-printing conditions, flexible and ductile samples with good dimensional stability and cohesion are obtained, as is proven by scanning electron microscopy (SEM) and tensile stress-strain tests.

scholarly journals Searching for Rheological Conditions for FFF 3D Printing with PVC Based Flexible Compounds

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 178 ◽  
Author(s):  
I. Calafel ◽  
R. H. Aguirresarobe ◽  
M. I. Peñas ◽  
A. Santamaria ◽  
M. Tierno ◽  
...  
Keyword(s):  
3D Printing ◽  
Thermal Degradation ◽  
Small Amplitude ◽  
Relaxation Modulus ◽  
Compression Modulus ◽  
Fused Filament Fabrication ◽  
Small Amplitude Oscillatory Shear ◽  
Poly Vinyl Chloride ◽  
G Ratio

Rheology is proposed as a tool to explore plasticized poly(vinyl chloride) (PVC) formulations to be used in the fused filament fabrication (FFF) 3D printing process and so manufactures flexible and ductile objects by this technique. The viscoelastic origin of success/failure in FFF of these materials is investigated. The analysis of buckling of the filament is based on the ratio between compression modulus and viscosity, but for a correct approach the viscosity should be obtained under the conditions established in the nozzle. As demonstrated by small amplitude oscillatory shear (SAOS) measurements, PVC formulations have a crystallites network that provokes clogging in the nozzle. This network restricts printing conditions, because only vanishes at high temperatures, at which thermal degradation is triggered. It is observed that the analysis of the relaxation modulus G(t) is more performing than the G″/G′ ratio to get conclusions on the quality of layers welding. Models printed according to the established conditions show an excellent appearance and flexibility, marking a milestone in the route to obtain flexible objects by FFF.

scholarly journals Additives Aid Switch to Protect the Photodegradation of Plastics in Outdoor Construction

2019 ◽  
Vol 22 (4) ◽  
pp. 277-282
Author(s):  
Salam A. Mohammed ◽  
Rahimi M. Yusop ◽  
Mohammed Abdulsattar Mohammed ◽  
Rasheed Abed Mohammed ◽  
Dina S. Ahmed ◽  
...  
Keyword(s):  
Schiff Base ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Surface Morphology ◽  
Ultraviolet Radiation ◽  
Vinyl Chloride ◽  
Leaching Test ◽  
Poly Vinyl Chloride ◽  
Effective Additive ◽  
Scanning Electron

Poly(vinyl chloride) photodecomposition films that contains melamine Schiff base (0.5% by weight) as photostabilizers upon preservation with an ultraviolet light (UV) was investigated. The photodecomposition rate constant was reduced significantly in existence of melamine Schiff base compared to PVC (blank). The Schiff base 1 was found to most effective additive in PVC photostabilization films. Photodecomposition rate content for PVC films containing Schiff base 1 was found to be 5 × 10-3 sec-1 compared to 8.7 × 10-3 sec-1 for blank film. Ultraviolet radiation aging behaviors of PVC films were studied through leaching test by measuring the degree of migration. The surface morphology of PVC films was inspected by scanning electron microscope.

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