Multifunktionale Polysiloxane für einen verbesserten Weichgriff von Textilien unter Erhalt der hydrophilen Eigenschaften

Ronge, Ramona; Möller, Martin (Thesis advisor); Böker, Alexander (Thesis advisor)

Aachen : Publikationsserver der RWTH Aachen University (2015)
Dissertation / PhD Thesis

Aachen, Techn. Hochsch., Diss., 2014


This thesis concerned the development of hydrophilic polysiloxan based softeners with strong adhesive properties. Functionalized polysiloxanes were designed and examined concerning their structure-response relationship on cotton and polyester fabrics. To ensure strong adhesive properties of the polysiloxanes two different binding concepts were investigated: first with covalent bonds and second with multiple hydrogen bonds.For the covalent binding concept in a first step comb-shaped PDMS-PEG were synthesized via hydrosilylation with poly(methyl hydrogen-stat-dimethyl siloxane) and poly(ethylene glycol)-monoallyl ether. Afterwards the hydroxy terminated PDMS-PEGs were functionalized with isocyanatopropyl triethoxysilane as binding moiety. Good adhesive properties were obtained with the customized polysiloxanes on cotton fabrics. Especially polysiloxanes with a high density of binding groups (PDMS-PEG 87/12-17 und 23/4-17) showed improved adhesive bond strength with triethoxysilane. The polysiloxane layer on the fabric was between 4-9 nm and increased with rising hydrophobicity of the polysiloxanes.Based on high polymer chain flexibility and only minor intermolecular interactions the polysiloxanes improved the soft handle of cotton fabric. The PDMS-PEGs with big polymer chain loops (100/4-7, 100/4.-17, 91/8-7, 91/-8-17 und 87/12-7) enhanced the soft handle significantly compared to the raw fabric. In particular the deformability of the fabrics, determined by the inner softness of a yarn, was influenced by the polysiloxanes. The hydrophilic properties of treated fabrics were measured by absorbance and rising properties of water. With higher HLB value of the polysiloxanes the hydrophilic properties of the treated fabrics increased. After the application of the polysiloxanes with a portion up to 60 vol% PDMS (23/4-7, 23/4-17, 30/9-10 und 87/12-17) the hydrophilic properties of cotton fabric was not diminished.Systematically varying polysiloxane properties such as the molecular weight, the density and length of hydrophilic sidechains yielded in PDMS-PEG 87/12-17, a polysiloxane featuring good soft handle together with adequate hydrophilic properties.The second binding concept, adhesion by hydrogen bonds, stands out due to their broad field of binding applications on various surfaces. Two different comb shaped polysiloxanes were prepared either with the coupler phenylchloroformiate or epoxy as terminal groups. Subsequently, the end groups of these starting compounds were functionalized with 2-(1-aminoethyl)imidazolidinone, the final binding group. The epoxide based synthesis proofed to be faster and more efficient.The functional polysiloxane formed a stable layer of about 5 nm on polyester fabric. In particular the polysiloxane 87/12 with a high density of binding groups was evenly applied to polyester fabric with an excellent permanence. The adhesive properties of PDMS-PEG 91/8-6-4 were improved with imidazolidinone functionalization compared to the previously hydroxyl functionalized polysiloxanes. Via the epoxide strategy prepared polysiloxanes showed with and without imidazolidinone comparably adhesive properties. Maybe the interactions between epoxides and fabric were sufficient for permanent adherence.The soft handle of polyester fabrics was significantly improved by applying imidazolidinone functionalized polysiloxanes such as polysiloxane 100/4, 91/8, 87/12 and 23/4. As observed for cotton the fabrics were easier to deform in accordance with softer handle. The application of imidazolidinone functionalized polysiloxanes did not lead to higher hydrophobicity of polyester fabrics. A high density of imidazolidinone (D:Dx < 4:1) rather enhanced the hydrophilicity. More than 40 vol% PEG (30/9-10 and 78/6/4) improved the hydrophilicity even further.Concluding the hydrogen bond based concept, the imidazolidinon functionalized polysiloxane 87/12 stood out by an even application and good durability on polyester fabric. The results of hydrophilicity and soft handle were comparably well for imidazolidinon functionalized polysiloxanes prepared via the epoxide route. To further increase the hydrophilicity a combination of PEG- and epoxy functional side chains is imaginable, where the epoxy functional chains are modified with the binding group. First experiments with such a polysiloxane 78/6/4 showed very good hydrophilic properties on polyester fabrics.