The effects of radiation cross-linking and process parameters on the behavior of polyamide 12 in vacuum thermoforming

2011 ◽  
Vol 52 (4) ◽  
pp. 884-892 ◽  
Author(s):  
A. Seefried ◽  
D. Drummer
Keyword(s):  
Process Parameters ◽  
Cross Linking ◽  
Polyamide 12 ◽  
Effects Of Radiation

Comparative study of thermoplastic liner materials with regard to mechanical and permeation barrier properties before and after cyclic thermal aging

2021 ◽  
Vol 63 (4) ◽  
pp. 311-316
Author(s):  
Simon Backens ◽  
Jan Siering ◽  
Stefan Schmidt ◽  
Nikolai Glück ◽  
Wilko Flügge
Keyword(s):  
Thermal Aging ◽  
Barrier Properties ◽  
Tensile Tests ◽  
Polyamide 6 ◽  
Pressure Vessels ◽  
Cross Linking ◽  
Polyamide 12 ◽  
Type Iv ◽  
Before And After ◽  
Permeation Properties

Abstract Lightweight pressure vessels of type IV for hydrogen storage consist of a thermoplastic inner liner, commonly from polyethylene or polyamide. The liner is the permeation barrier against the compressed gas and must prevent the formation of cracks, also after temperature changes, for example after refueling processes. In the present work high-density polyethylene, cross-linked polyethylene, polyamide 6 and polyamide 12 were characterized by tensile tests, single notch impact tests and permeations measurements before and after a cyclic thermal aging process. The aging only lead to slight changes of mechanical properties due to post-crystallization, but to a significant decrease of permeation properties. This decrease was contributed to weakened, amorphous regions where chain splitting occurred. Considerable differences in properties resulted from different peroxide cross-linking times of polyethylene at the same temperature. A longer holding time at 200 °C led to an improvement in impact strength by a factor of more than three. However, the permeation properties decreased by about 50 %, indicating that peroxide cross-linking in the melt inhibited the formation of crystalline regions.

FTIR SPECTROSCOPIC STUDIES ON CROSS LINKING OF SU-8 PHOTORESIST

COSMOS ◽  
2013 ◽  
Vol 09 (01) ◽  
pp. 37-46 ◽  
Author(s):  
S. M. P. KALAISELVI ◽  
T. L. TAN ◽  
R. S. RAWAT ◽  
P. LEE ◽  
S. P. HEUSSLER ◽  
...  
Keyword(s):  
Process Parameters ◽  
Spectroscopic Studies ◽  
Exposure Dose ◽  
Good Evidence ◽  
Pattern Generation ◽  
Cross Linking ◽  
X Ray ◽  
Dosage Requirement ◽  
Negative Tone ◽  
Micro Structures

The usage of chemically-amplified, negative tone SU-8 photoresist is numerous, spanning industrial, scientific and medical fields. Hence, in this study, some preliminary studies were conducted to understand the dosage and heat treatment requirements of the SU-8 photoresist essential for pattern generation using X-ray lithography. In this work, using Synchrotron as the X-ray source, SU-8 photoresist was characterized for X-ray lithography in terms of its process parameters such as X-ray exposure dose, post exposure bake (PEB) time and temperature for various photoresist thicknesses which is considered worthwhile in view of applications of SU-8 for the fabrication of very high aspect ratio micro structures. The process parameters were varied and the resultant cross linking of the molecular chains of the photoresist was accurately monitored using a Fourier Transform Infra-Red (FTIR) spectrometer and the results are discussed. The infrared absorption peak at 914 cm-1 in the spectrum of the SU-8 photoresist was found to be a useful indicator for the completion of cross linking in the SU-8 photoresist. Results show that the cross linking of the SU-8 photoresist is at a higher rate from 0 J/cm3 to 30 J/cm3 after which the peak almost saturates regardless of the PEB time. It is a good evidence for the validation of dosage requirement of SU-8 photoresist for effective completion of cross linking, which in turn is a requirement for efficient fabrication of micro and nano structures. An analogous behavior was also observed between the extent of cross linking and the PEB time and temperature. The rate of cross linking declines after a certain period of PEB time regardless of PEB temperature. The obtained results also show a definite relation between variation of the absorbance area of the peak at 914 cm-1 and the X-ray exposure dose.

Experimental Study on Laser Plasticizing Polyamide 12

2012 ◽  
Vol 472-475 ◽  
pp. 2514-2518
Author(s):  
Wen Sheng Tan ◽  
Jian Zhong Zhou ◽  
Shu Huang ◽  
Yu Jie Fan
Keyword(s):  
Process Parameters ◽  
Beam Diameter ◽  
Laser Materials ◽  
Influence Of Process Parameters ◽  
Scanning Velocity ◽  
Polyamide 12 ◽  
Injection Process ◽  
Orthogonal Experiments ◽  
Environment Temperature ◽  
Sequence Rule

Considering the efficiency and microscale requirement of melting polymer in micro-injection process, we present an experimental analysis of the CO2 laser irradiating Polyamide 12 (PA12) based on the photo-thermal effect of laser-materials interaction. The orthogonal experiments of laser plasticizing were designed by Taguchi method of Minitab software, the influence of process parameters on PA12 plasticization was investigated, and the effect sequence rule of the experiment parameters to melting depth was analyzed. Accordingly，the optimal process parameters combination on PA12 plasticization were obtained，i.e. laser power 3 W, beam diameter 2 mm, scanning velocity 200 mm/min, scanning distance 0.5 mm and environment temperature 20°C.

Influence of Cross-Linking and Process Parameters on the Separation Performance of Poly(dimethylsiloxane) Nanofiltration Membranes

2005 ◽  
Vol 44 (9) ◽  
pp. 3238-3248 ◽  
Author(s):  
John P. Robinson ◽  
E. Steve Tarleton ◽  
Katrin Ebert ◽  
Chris R. Millington ◽  
Arian Nijmeijer
Keyword(s):  
Process Parameters ◽  
Cross Linking ◽  
Separation Performance ◽  
Nanofiltration Membranes

scholarly journals Enzymatic cross-linking of pectin in a high-pressure foaming process

2020 ◽  
Vol 11 (3) ◽  
pp. 2040-2047 ◽  
Author(s):  
Judith Wemmer ◽  
Sarah Holtgrave ◽  
Laura Wiest ◽  
Martin Michel ◽  
Martin E. Leser ◽  
...  
Keyword(s):  
High Pressure ◽  
Process Parameters ◽  
Foam Stability ◽  
Cross Linking ◽  
Viable Option ◽  
Process Kinetics ◽  
Foaming Process

This study demonstrates that integrating enzymatic cross-linking in a high-pressure foaming process is a viable option to increase foam stability when well aligning the relevant process parameters and process kinetics.

scholarly journals Research on Recovery Mechanism and Process of Waste Thermosetting Phenolic Resins Based on Mechanochemical Method

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Jian Hu ◽  
Huifang Dong ◽  
Shouxu Song
Keyword(s):  
Process Parameters ◽  
Phenolic Resin ◽  
Rotation Speed ◽  
Recovery Process ◽  
The Body ◽  
Cross Linking ◽  
Recovery Method ◽  
Recovery Mechanism ◽  
The Cross ◽  
Feed Volume

The present study analyzed the recovery mechanism of the thermosetting phenolic resin waste, optimizing the recovery process parameters, based on the mechanochemical recovery method. The physical and chemical structure of the ultrapulverized phenolic resin powder was characterized by the low-field NMR (nuclear magnetic resonance), IR (infrared spectroscopy), and SEM (scanning electron microscopy). The recovery process parameters were designed by using the response surface analysis method, and the multiple quadratic regression model was established and the multiobjective process parameter was optimized. The results show that the body network structure of the material is destroyed during the crushing process. The intensity of the internal cross-linking signal is reduced and tends to be stable at about 60%, when the particle size exceeds 120 mesh. The cross-linking bonds methylene (-CH2-) in the main chain of the molecular chain and the C-O bond in the methylol group on the branch are broken. The tensile strength of the recycled sheet made of the phenolic resin powder is 8.27 MPa, and the bending strength is 17.76 Mpa through the mechanical properties test. The influences on the change rate of the cross-linking signal intensity and the yield of the recycled powder are in the following order: rotation speed, feed size, time, and feed volume. The best recovery parameters are as follows: rotation speed of 2820 r/min, time of 80 min, feed particle diameter of 0.43 mm, and feed volume of 60 g.

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