Post on 24-Jun-2020
| 29.03.2017| DFT
Combination of plasma treatment and sol-gel chemistry for enhanced rubber / fibre
adherence
Kristina Klinkhammer, Esther Rohleder, Maike Rabe, Eberhard Janssen
Aachen-Dresden-Denkendorf Deutsches Fachkolloquium Textil 28.-29.03.2017, Aachen
| 29.03.2017| DFT
Content
textile reinforcement material properties application standard functionalisation
aim of the project plasma technology sol-gel technology results summary
| 29.03.2017| DFT
Textile Reinforcement
textile reinforcement • are embedded in a second material, e.g. rubber • increase stability and durability of a product • many different application
Cam-, V-belts
tyres
conveyor belts hose
| 29.03.2017| DFT
Reinforced plastic - material
textile material: • polyester • polyamide 6.6 (nylon) • p-aramide • other
materials for embedding matrix:
• natural rubber • synthetic rubber ( e.g. VP, SBR) • plastics (e.g. PU, PVC, PE)
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Reinforced plastic - properties
• textile reinforcement are embedded in (rubber) matrix to enhance
product properties
• rubber properties differ from textile properties, e.g.
• surface morphology
• flexibility
• E modulus
• low reactivity and low polarity of textile fibres
need for chemical functionalisation for better adherence
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Reinforced plastic - properties
material E modulus (N/mm²) polyethylen-terephthalat (PET)
2800-3000
PA6 3000 / 1000 PA66 3100 / 1100 aramide 59000-100000 natural rubber 50 SBR 10 PU 20-220 PVC 3000 PE 720-1100
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Reinforced plastic - functionalisation
standard for water based systems: RFL (resorcinol–formaldehyde–latex) preparation: 1. reaction between resorcinol and formaldehyde RF resin (binds to
fibre) 2. introduction of latex (rubber-like, bonds to rubber by co-
vulcanization) 3. dipping of fibres in RFL 4. heat treatment (drying 130-170 °C, curing 190-240 °C)
RF resin
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RFL - problems
formaldehyde:
great interest to substitute RFL dip
reclassified from class 2 to class 1B (carcinogenic) US and EU
impact on regulations currently discussed evaluating endocrine disruptive properties
done in 2016 (in CoRAP) impact on future regulations open
resorcinol:
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Research project - aims
• adhesion improvement between textile reinforcement and rubber matrix
• substitution of RFL dip • use of more environmental friendly chemicals • combination of plasma and sol-gel-chemistry
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Surface functionalisation - plasma technology
Plasma (fourth state of matter) • nature: thunderbolt, solar wind • artificial: by electrical discharge • ionised gas • neutral and electrical charged species (electrons,
ions, neutral particles)
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w.w
ikip
edia
.de
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Plasma technology – types of plasma
atmospheric pressure plasma: • pressure: approx. 1 bar • energy: electric discharge • Corona / DBD 5 – 100 kHz • DBD (dielectric barrier discharge) • rel. high temperature • high process gas consumption
low pressure plasma: • pressure: 0.5 mbar • energy: RF-Generator • homogenous reactions • low temperature • low process gas consumption • closed circuit: toxic gases possible
| 29.03.2017| DFT
Surface functionalisation – sol-gel technology
originally: wet-chemical process for surface functionalisation
SiR
RO OROR
SiR
RO OHOR
H2OH+ / OH-
+
SiR
RO OHOR
SiR
OH OROR
SiR
O OHOR
SiR
ROOR
+- H2O
1. hydrolysis:
2. condensation:
XR’-Si-(OR)3 with X = functional group R’ = alkyl or aryl, R = mainly CH3 or CH2CH3 OR crosslinking and film formation X special functions of the film
precursors:
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sol application via padding, drying and polymerisation
drying : evaporation of the solvent (water, ethanol) increase of sol concentration condensation of particles and film formation (polymerisation)
fibre fibre fibre
Sol-gel-technology - film formation
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aqueous dispersion of silane (mix)
application
conventional dryer (oven)
plasma
a)
b)
Experimental
• material: polyester fibres for embedding in rubber • silanes with different functionalities: alky, amino, vinyl, mercapto,
glycidoxy, … • drying and condensation (polymerisation): oven or plasma
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Analytics
• hydrophilicity (droplet test)
• functional groups (KMnO4)
• elemental composition (EDX)
• surface morphology (REM)
• adhesion (peel test)
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Results: hydophilicity / hydrophobicity
droplet test: absorption time of water droplet
hydrophilic: short absorption time
plasma decreases absorption time
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Detection of functional groups: KMnO4
violett solution becomes clear by reaction with double bonds and other functional groups
00,5
11,5
22,5
3
350 450 550 650
Adso
rban
ce
wave lengths (nm)
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Results: REM / EDX
Si localised around fibres and in interspaces
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Results: REM / EDX
coating with 10% vinylsilane
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Results: REM / EDX
coating with 4% vinylsilane
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Results: peeltest samples
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Results: adhesion
name functionalisation treatment adhesion force (N/25mm)
raw PES
none none 106
raw PES
RFL (standard) oven 185
MG33 glycidoxy silane oven 118 MG34 glycidoxy silane plasma 182 MG127 amino silane plasma 189
plasma treatment of functionalised fibres results in higher adhesion than
oven heating
variation of chemical concentration / variation results in high adhesion
force
| 29.03.2017| DFT
Summary
• polyester fibres were functionalised with silanes and treated with
plasma or in the oven
• plasma treatment shows clear advantages in comparison to oven
treatment
• the finishing is located around the fibres and in interspaces
• high adhesion forces comparable to RFL dip are achieved
| 29.03.2017| DFT
Acknowledgment Acknowledgment
Many thanks to the colleagues and students of FTB at Niederrhein
University of Applied Science: Noman Mughal, Alexandra Glogowski and
Anne Hartmann
Thanks to German Federal Ministry of Education and
Research (BMBF) for financial support (grant no.
03X0129B).
| 29.03.2017| DFT
Dr. Kristina Klinkhammer, phone: +49 (0)2161-186 6042 Dr. Esther Rohleder, phone: +49 (0)2161-186 6008 Prof. Dr. Maike Rabe, phone: +49 (0)2161-186 6110 Prof. Dr. Eberhard Janssen, phone: +49 (0)2161-186 6042 Niederrhein University of Applied Sciences Research Institute for Textile and Clothing (FTB) Richard-Wagner-Str. 97 41065 Mönchengladbach Germany
Contact