Poly 2,6-dimethyl 1,4 Phenylene Oxide

Because most of the trace structural units in PPO resin contain labile phenolic hydroxyl groups, Chan and co-workers [74] thought that these functional groups could serve as a handle for attaching a more sensitive NMR nucleus which would give stronger and well-separated signals for the different structural units. The particular nucleus 

Brevand and Granger [75] carried out a quantitative analysis on three samples which can be identified as follows (A) PPO resin, (B) PPO and polystyrene alloy blend (1 1, w/w, PPO/PS), (C) PPO and high-impact polystyrene alloy blend (1 1, w/wy PPO/HIPS). Results are summarised in Table 8.7. 

On the basis of this technique, they obtained the hydroxyl concentration of normal phenolic ends 2, phenolic ends 4, and phenolic groups on the backbone 8 or 9, as well as the number-average molecular weight of the polymers. 

Hydroxy contents obtained by this method agree well with those obtained by IR spectroscopy. 

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Alkylated phenol derivatives are used as raw materials for the production of resins, novolaks (alcohol-soluble resins of the phenol—formaldehyde type), herbicides, insecticides, antioxidants, and other chemicals. The synthesis of 2,6-xylenol [576-26-1] h.a.s become commercially important since PPO resin, poly(2,6-dimethyl phenylene oxide), an engineering thermoplastic, was developed (114,115). The demand for (9-cresol and 2,6-xylenol (2,6-dimethylphenol) increased further in the 1980s along with the growing use of epoxy cresol novolak (ECN) in the electronics industries and poly(phenylene ether) resin in the automobile industries. The ECN is derived from o-cresol, and poly(phenylene ether) resin is derived from 2,6-xylenol. 

Poly-2,6-dimethyl phenylene oxide (PPO) and certain related materials are similar to the nylons but have superior heat resistance. These polymers are somewhat liable to stress-cracking problems. 

Nylon, polyacetal, polycarbonates, poly(2,6-dimethyl)phenylene oxide (PPO), polyimides, polyphenylene sulfide (PPS), polyphenylene sulfones, polyaryl sulfones, polyalkylene phthalates, and polyarylether ketones (PEEK) are stiff high-melting polymers which are classified as engineering plastics. The formulas for the repeating units of some of these engineering plastics are shown in Figure 1.15. 

Polyphenylene Oxide. This is actually poly (2,6-dimethyl-phenylene oxide) and was introduced by General Electric as the first... 

Fig. 5. Miscibility of poly(2,6-dimethyl phenylene oxide) (PPO) and random copolymers of styrene and o-bromostyrene (7), p-fluorostyrene (2), p-bromostyrene (i), o-chlorostyrene (4), p-chlorostyrene (5), and o-fluorostyrene (<5) for 50/50 blends. Miscibility occurs to the left of the curves (after Ref. [29])...

After having studied in our laboratory, polymer blends of amorphous polymers poly-c-caprolactone and poly (vinyl chloride) (1,2) (PCL/ PVC), blends with a crystalline component PCL/PVC (3,4), poly(2,6-dimethyl phenylene oxide) (PPO) with isotactic polystyrene (i-PS) (5) and atactic polystyrene (a-PS) with i-PS (6), we have now become involved in the study of a blend in which both polymers crystallize. The system chosen is the poly(1,4-butylene terephthalate)/poly(ethylene terephthalate) (PBT/PET) blend. The crystallization behavior of PBT has been studied extensively in our laboratory (7,8) this polymer has a... 

Figure 7. Electrolytic oxidation of 2,6-dimethylphenol. Key O, poly(2,6-dimethyl phenylene oxide) , oligo(2,6-dimethyl phenylene oxide) (1, 2,2 6,6 -tetramethylbiphenoquinone, 0,1 M dimethylphenol in 20% methanol-dichloro-methane containing 0,2 M tetraethyl ammonium bromide, current density 10 mA/cm platinum counter electrodes with saturated calomel reference under anaerobic condition at room temperature.

PROPERTIES OF SPECIAL INTEREST H-H PS is Completely miscible with poly(2,6-dimethyl phenylene oxide) in the same way that H-T PS is miscible with that polymer. ... 

Polystyrene Poly(2,6-dimethyl phenylene oxide) Cizak (1968), Stoelting et ai (1969), MacKnight et ai (1971)... 

Addition of AN to a level of 40% (NBR-40) destroys the phase boundaries entirely, resulting in the microheterogeneous system shown in Figure 3.10. The phase domains ( 100 A) shown in Figure 3.10 are clearly smaller than the polymer molecules themselves, yet the material is not totally compatible. Only a few cases are known in which the phase division in blends is so fine such cases include the IPN s discussed in Chapter 8 and the poly(2,6-dimethyl phenylene oxide)/polystyrene blend described in Section 9.7.1. 

Some commodity plastics have low impact strengths. Of course, the impact strength can be strongly increased by blending with other polymers (see also Section 35.3.5.3), which, in the case of the quite brittle poly(styrene), can be achieved by copolymerization, by graft polymerization in the presence of polydienes, or by styrene polymerization in the presence of poly (2,6-dimethyl phenylene oxide.) Poly(vinyl chloride) is also made less brittle by reinforcing with poly(acrylates). 

PPO Poly(2,6-dimethyl phenylene oxide) General Electric, U.S. 

Handa, Y.P., S. Lampron, and MT. Oneill, On the Plasticization of Poly(2,6-Dimethyl Phenylene Oxide) by Col. Journal of Polymer Science Part B-Polymer Physics, 1994.32(15) p. 2549-2553. 

PPO n. Poly(2,6-dimethyl phenylene oxide. Manufactured by General Electric, USA. n. Abbreviation for poly(phenylene oxide). 

PS has a low heat distortion temperatnre (HDT) and poly(2,6-dimethyl phenylene oxide) (PPO) has low processability. Blending PS with PPO leads to improved HDT and economy and processing characteristics [17-19]. Applications include appliance housings, automotive dashboards, pump components and television components. PS and polymethyl methacrylate (PMMA) form immiscible blends that exhibit a pearlescent appearance and are used for decorative applications [20]. 

Various synthetic approaches have been demonstrated for the synthesis of PAEs since early days [35 0], PAEs were synthesized by Ullmann condensation between bisphenols and aryl fcis-halide monomers using Cu(I) salt/pyridine as catalyst [36], General Electric developed the first commercially successful PAE poly(2,6-dimethyl phenylene oxide) (PPO) [38], It was prepared by oxidative coupling of 2,6-dimethyI phenol. However, this process has its own restrictions, because it does not allow much structural variation or inclusion of any electron-withdrawing group into the polymer main chain. First attempts to synthesize polysulfones (PSF) were successfully done by Friedel-Crafts sulfonylation reaction of arylenedisulfonyl chlorides, for example, diphenyl ether-4,4 -disulfonyl chloride with diaryl ethers, for example, diphenyl ether, or by self-condensation of 4-phenoxy benzene sulfonyl chloride in the presence of FeCls [41], Whereas the former reaction involves side reactions (sulfonylation not only in the para- but also in the ort/io-position), the latter produces only the desired linear all-para products. 

From such information, it may be found that the system poly(2,6-dimethyl phenylene oxide)-h/md-polystyrene is miscible but that poly(dimethyl silox-ane), which is so different from the others, should be immiscible with all of them. 

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