Plastic‐rubber composite, 2. Polymer‐polymer interdiffusion at the phase boundary of poly(oxy‐2,6‐dimethyl‐1,4‐phenylene) and poly(styrene‐co‐butadiene)

Abstract

Interdiffusion of poly(oxy-2,6-dimethy1-1 ,Cphenylene) (PPE) and polystyrene (PS) sequences is the key step in the formation of the so-called plastic-rubber composite (Kunststoff-Kautschuk-Verbund, K & K-V). This new process links PPE and poly(styrene-co-butadiene) rubber (SBR) during the vulcanization of the rubber, without the aid of any adhesives. Polystyreneblock-polybutadiene (SB) is used as model for SBR. As PPE and polystyrene (PS) are fully mutually compatible polymers, polymer-polymer interdiffusion occurs easily for PPE and the PS blocks. This is shown by electron microscopy. The thickness of the interdiffusion zone correlates to the PS block length. The respective butadiene block forms a layer on top of the interdiffusion zone. SBR with a high styrene content of at least 71 wt.-% is also compatible with PPE. The interdiffusion kinetics of the system PPE-SBR follows Fickian behaviour. The diffusion coefficients are smaller than for the system PPE-PS. Although PPE and SBR with lower PS content, as it is used for the K & K-V, are not compatible, interdiffusion occurs at the phase boundary. The thickness of the diffusion zone depends on the styrene content of the SBR. For SBR samples with 40 and 23,5 wt.-% styrene, zones of SO and 15 nm thickness are found. ~ a) part 1: cf. ' ).

Direct bonding between poly(oxy‐2,6‐dimethyl‐1,4‐phenylene) and rubber with radicals

“…In 1990, Machate et al investigated a combination of PXE and polystyrene 16, 17. According to their results, polystyrene would diffuse into PXE above 180°C.…”

“…According to AFM, a specific layer in which viscoelasticity is between that of PPE‐1 and that of rubber was observed. In the case of PPE‐1 and SBR‐1, the AFM observation shows an ∼96‐nm‐thick layer (i.e., the diffusion layer) between PPE‐1 and SBR‐1, because PPE‐1 and SBR‐1 can interdiffuse each other 16, 17. Figure 2 shows the interface between PPE‐1 and E‐03 using AFM observation.…”

Experimental and simulative investigation of a multistage 2K injection molding process of PA6 and EPDM

“…Interdiffused polymer chains that have formed a network of entanglements may thus be fixed by the crosslinking reaction. 2,9 The adjustments result in a significant increase in adhesion.…”

“…Subsequent crosslinking of the SBR fixes these interdiffusions. 1,2 Covalent bonds are possible between PPE and special peroxide-crosslinked ethylene-propylene-diene rubber (EPDM). 3 Direct adhesion between polyamide (PA) or polybutylene terephthalate (PBT) and liquid silicone rubber (LSR) has also been the subject of various research papers in the past.…”

“…This material combination results in the interdiffusion of styrene segments and the formation of a distinct interdiffusion zone. Subsequent crosslinking of the SBR fixes these interdiffusions 1,2 . Covalent bonds are possible between PPE and special peroxide‐crosslinked ethylene‐propylene‐diene rubber (EPDM) 3 .…”