scholarly journals Simulation of asymmetrical multilayer flat film coextrusion regarding slip at the wall and interfacial slip at the polymer-polymer interface

2019 ◽  
Author(s):  
C. Kneidinger ◽  
M. Laengauer ◽  
E. Mayrhofer ◽  
G. Zitzenbacher ◽  
J. Miethlinger
2000 ◽  
Vol 629 ◽  
Author(s):  
John V. St. John ◽  
Patty Wisian-Neilson

ABSTRACTPoly (methylphenylphosphazene) (PMPP) is an example of a unique class of inorganic polymers with alternating – (P=N)– backbones. Chemical modification of bulk PMPP can result in changes of physical properties such as chemical resistance, onset temperature of thermal degradation, elasticity, and flexibility. Surface modification of PMPP allows tailoring of the chemical properties at the polymer interface while maintaining the integrity of the bulk polymer. In this research, PMPP thin films were treated to form carboxylate or carboxylic acid groups at the surface. Surface modification was monitored by following changes in contact angle. The hydrophobic/hydrophilic interactions of carboxylated PMPP surfaces allow for mesoscale interactions of thin polymer films.


2000 ◽  
Vol 629 ◽  
Author(s):  
Jonathan S. Schulze ◽  
Timothy P. Lodge ◽  
Christopher W. Macosko

ABSTRACTThe reaction of perdeuterated amino-terminal polystyrene (dPS-NH2) with anhydrideterminal poly(methyl methacrylate) (PMMA-anh) at a PS/PMMA interface has been observed with forward recoil spectrometry (FRES). Bilayer samples were constructed by placing thin films of PS containing ∼8.5 wt % dPS-NH2 on a PMMA-anh layer. Significant reaction was observed only after annealing the samples at 174°C for several hours, a time scale at least two orders of magnitude greater than the time required for the dPS-NH2 chains to diffuse through the bulk PS layer. The topography of the interfacial region as copolymer formed was measured using atomic force microscopy (AFM). Roughening of the PS/PMMA interface was observed to varying degrees in all annealed samples. Furthermore, the extent of this roughening was found to depend on the PS matrix molecular weight. Reaction in the samples with a high molecular weight PS matrix resulted in a root mean square roughness approximately equal to the radius of gyration Rg of the copolymer. However, approximately twice as much roughening was observed in the low molecular weight PS matrix. This study reveals how the molecular weight of one of the phases can affect the rate of reaction at a polymer/polymer interface.


2015 ◽  
Vol 84 (8) ◽  
pp. 591-595 ◽  
Author(s):  
Yukiko IZUMI ◽  
Naoki BADEN ◽  
Kazuhiro MATSUDA

2021 ◽  
Vol 278 ◽  
pp. 116797
Author(s):  
Nidhi Yadav ◽  
Nikita Kumari ◽  
Yoshito Ando ◽  
Shyam S. Pandey ◽  
Vipul Singh

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 594
Author(s):  
Pavel Brdlík ◽  
Martin Borůvka ◽  
Luboš Běhálek ◽  
Petr Lenfeld

The influence of additives such as natural-based plasticiser acetyl tributyl citrate (ATBC), CaCO3 and lignin-coated cellulose nanocrystals (L-CNC) on the biodegradation of polylactic acid (PLA) biocomposites was studied by monitoring microbial metabolic activity through respirometry. Ternary biocomposites and control samples were processed by a twin-screw extruder equipped with a flat film die. Commonly available compost was used for the determination of the ultimate aerobic biodegradability of PLA biocomposites under controlled composting conditions (ISO 14855-1). In addition, the hydro-degradability of prepared films in a freshwater biotope was analysed. To determine the efficiency of hydro-degradation, qualitative analyses (SEM, DSC, TGA and FTIR) were conducted. The results showed obvious differences in the degradation rate of PLA biocomposites. The application of ATBC at 10 wt.% loading increased the biodegradation rate of PLA. The addition of 10 wt.% of CaCO3 into the plasticised PLA matrix ensured an even higher degradation rate at aerobic thermophilic composting conditions. In such samples (PLA/ATBC/CaCO3), 94% biodegradation in 60 days was observed. In contrast, neat PLA exposed to the same conditions achieved only 16% biodegradation. Slightly inhibited microorganism activity was also observed for ternary PLA biocomposites containing L-CNC (1 wt.% loading). The results of qualitative analyses of degradation in a freshwater biotope confirmed increased biodegradation potential of ternary biocomposites containing both CaCO3 and ATBC. Significant differences in the chemical and structural compositions of PLA biocomposites were found in the evaluated period of three months.


2021 ◽  
pp. 105678952110112
Author(s):  
Hehua Zhu ◽  
Xiangyang Wei ◽  
J Woody Ju ◽  
Qing Chen ◽  
Zhiguo Yan ◽  
...  

Strain hardening behavior can be observed in steel fiber reinforced concretes under tensile loads. In this paper, a statistical micromechanical damage framework is presented for the strain hardening steel fiber reinforced concrete (SH-SFRC) considering the interfacial slip-softening and matrix spalling effects. With a linear slip-softening interface law, an analytical model is developed for the single steel fiber pullout behavior. The crack bridging effects are reached by averaging the contribution of the fibers with different inclined angles. Afterwards, the traditional snubbing factor is modified by considering the fiber snubbing and the matrix spalling effects. By adopting the Weibull distribution, a statistical micromechanical damage model is established with the fracture mechanics based cracking criteria and the stress transfer distance. The comparison with the experimental results demonstrates that the proposed framework is capable of reproducing the SH-SFRC’s uniaxial tensile behavior well. Moreover, the impact of the interfacial slip-softening and matrix spalling effects are further discussed with the presented framework.


2020 ◽  
Vol 41 (2) ◽  
pp. 109-118
Author(s):  
Esmail Sharifzadeh ◽  
Yasahr Amiri

Abstract In this work, the effects of the morphological variation and the polymer/polymer interface on the tensile modulus of binary polymer blends were evaluated using a combined modeling method. The characteristics of the polymer/polymer interface region were evaluated using a neural network system and the results were used to improve the analytical model. The model accuracy was investigated by comparing its predictions with the tensile test results of some prepared iPP/PA blend samples and also some other data from literature which revealed an acceptable accuracy (error < 5%).


2021 ◽  
Vol 155 (5) ◽  
pp. 054904
Author(s):  
Leon A. Smook ◽  
Guido C. Ritsema van Eck ◽  
Sissi de Beer

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