Reactive blend of epoxy‐novolac resin and epoxide‐terminated low‐molecular‐weight poly(phenylene oxide)

The epoxide‐terminated low‐molecular‐weight poly(phenylene oxide) (PPO), EPPO, was synthesized by modifying the terminal hydroxyl group of PPO and it was reactively blended with epoxy‐novolac resin (EPN). The curing kinetics, phase morphology, thermal stability, dielectric property, and water absorption behavior of the cured EPN/EPPO blends were investigated and compared with the unmodified EPN/PPO blends. As revealed by the FTIR and DSC analysis, EPPO takes part in the curing reaction and forms a reactive blend with EPN. The curing rate of both EPN/PPO and EPN/EPPO blends first increases and then decreases with increasing the PPO or EPPO fraction. The blends have lower degree of curing than neat EPN, due to the steric hindrance effects of PPO or EPPO. Because of the reaction between blend components, EPN/EPPO blends show faster curing rate and higher degree of curing than the corresponding EPN/PPO blends. The reactive blending improves the dispersion of EPPO in EPN matrix and the EPN/EPPO blend forms a co‐continuous morphology even at a low EPPO content, compared to the typical sea‐island morphology of the EPN/PPO blend. The EPN/EPPO blend has remarkable smaller dielectric constant, dissipation factor, and water absorption than neat EPN. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

PPO–PC block‐copolymers used as compatibilizers in PS/PC blends

Block‐copolymers containing poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) and polycarbonate of bisphenol A (PC) segments were employed as compatibilizers in polystyrene (PS)/PC blends. Block‐copolymers were prepared starting from oligomeric diols‐terminated PPO and PC. The poly(phenylene ethers) was obtained by oxidative coupling of 2,6‐dimethyl‐phenol in presence of tetramethyl bisphenol A. The copolymers were obtained with a chain extension reaction between the starting oligomers using bischloroformate of bisphenol A or phosgene as coupling agent. PS/PC blends, cast from chloroform solutions or mixed by melt, were studied by differential scanning calorimeter (DSC), dynamic‐mechanical thermal analysis (DMTA), and optical microscopy (OP). The thermal and morphological analyses showed a clear compatibilization effect between PS and PC, if PPO–PC copolymer is added when blending is performed in the melt; in addition, also mechanical properties are increased when compared with blends without PPO–PC. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4654–4660, 2006     

Blends of SBS triblock copolymer with poly(2,6‐dimethyl‐1,4‐phenylene oxide)/polystyrene mixture

Blends of styrene–butadiene–styrene (SBS) or styrene–ethylene/1‐butene–styrene (SEBS) triblock copolymers with a commercial mixture of polystyrene (PS) and poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) were prepared in the melt at different temperatures according to the chemical kind of the copolymer. Although solution‐cast SBS/PPO and SBS/PS blends were already known in the literature, a general and systematic study of the miscibility of the PS/PPO blend with a styrene‐based triblock copolymer in the melt was still missing. The thermal and mechanical behavior of SBS/(PPO/PS) blends was investigated by means of DSC and dynamic thermomechanical analysis (DMTA). The results were then compared to analogous SEBS/(PPO/PS) blends, for which the presence of a saturated olefinic block allowed processing at higher temperatures (220°C instead of 180°C). All the blends were further characterized by SEM and TGA to tentatively relate the observed properties with the blends' morphology and degradation temperature. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2698–2705, 2003     

Synthesis,characterization and thermal properties of functionalized poly(2,6‐dimethyl‐1,4‐phenylene oxide)s containing ethylenic,aldehydic, hydroxyl and acrylate pendant groups

New functionalized poly(2,6‐dimethyl‐1,4‐phenylene oxide)s (PPOs) containing ethylenic, aldehydic, hydroxyl and acrylate pendant groups were synthesized and their structure, properties and curing kinetics were investigated. The incorporation of polar functional groups resulted in an improvement in the glass transition temperature in the order aldehydic PPO > acrylate PPO > hydroxyl PPO > vinyl PPO > brominated PPO > pristine PPO. Upon thermal curing, the electron‐donating substituent in the vinyl PPO resulted in an increase in the activation energy in the order –Pr, –Bu > –Ph > –H, whereas the electron‐withdrawing substituent in the acrylate PPO caused a slight decrease in the activation energy. Copyright © 2011 Society of Chemical Industry     

Novel polyisobutylene stars. XXIII. Thermal,mechanical, and processing characteristics of poly(phenylene ether)/polydivinylbenzene(polyisobutylene‐b‐polystyrene)37 blends

The objective of these investigations was to increase the use temperature of novel star‐block polymers consisting of a crosslinked polydivinylbenzene (PDVB) core from which radiate multiple poly(isobutylene‐b‐polystyrene) (PIB‐b‐PSt) arms, abbreviated by PDVB(PIB‐b‐PSt)_n. We achieved this objective by blending star‐blocks with poly(phenylene oxide) (PPO) that is miscible with PSt. Thus, various PPO/PDVB(PIB‐b‐PSt)_n blends were prepared, and their thermal, mechanical, and processing properties were investigated. The hard‐phase glass‐transition temperature of the blends could be controlled by the amount (wt %) of PPO. The blends displayed superior retention of tensile strengths at high temperatures as compared to star blocks. The melt viscosities of blends with low weight percentages of PPO were lower than those of star blocks. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2866–2872, 2002     

Phase behavior of binary and ternary blends of poly(styrene‐co‐methacrylic acid), poly(styrene‐co‐4‐vinylpyridine), and poly(2,6‐dimethyl‐1,4‐phenylene oxide)

Poly(styrene‐co‐methacrylic acid) (PSMA) and poly(styrene‐co‐4‐vinylpyridine) (PS4VP) of different compositions were prepared and characterized. The phase behavior of these copolymers as binary PSMA/PS4VP mixtures or with poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) as PPO/PSMA or PPO/PS4VP and PPO/PSMA/PS4VP ternary blends was investigated by differential scanning calorimetry (DSC). This study showed that PPO was miscible with PS4VP containing up to 15 mol % 4‐vinylpyridine (4VP) but immiscible with PS4VP‐30 (where the number following the hyphen refers to the percentage 4VP in the polymer) and PSMA‐20 (where the number following the hyphen refers to the percentage methacrylic acid in the polymer) over the entire composition range. To examine the morphology of the immiscible blends, scanning electron microscopy was used. Because of the hydrogen‐bonding specific interactions that occurred between the carboxylic groups of PSMA and the pyridine groups of PS4VP, chloroform solutions of PSMA‐20 and PS4VP‐15 formed interpolymer complexes. The obtained glass‐transition temperatures (T_g's) of the PSMA‐20/PS4VP‐15 complexes were found to be higher than those calculated from the additivity rule. Although, depending on the content of 4VP, the shape of the T_g of the PPO/PS4VP blends changed from concave to S‐shaped in the case of the miscible blends, two T_g were observed with each PPO/PS4VP‐30 and PPO/PS4VP‐40 blend. The thermal stability of the PSMA‐20/PS4VP‐15 interpolymer complexes was studied by thermogravimetry. On the basis of the obtained results, the phase behavior of the ternary PPO/PSMA‐20/PS4VP‐15 blends was investigated by DSC. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Characterization of polymer systems based on sulfonated poly(2,6‐dimethyl‐1,4‐phenylene oxide)

The sulfonation reaction of poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) has been carried out, incorporating the resulting product into pure PPO to study, in forthcoming research, the electrical and mechanical features of the composites with regard to their performance in fuel cells. Pure sulfonated polymers and their blends have been characterized from a microstructural and electrical point of view, by means of X‐ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC) and complex impedance spectroscopy. Membranes have been manufactured with excellent ionic conductivity at room temperature. © 2000 Society of Chemical Industry     

Effects of extensional flow on properties of polyamide‐66/poly(2,6‐dimethyl‐1,4‐phenylene oxide) blends: A study of morphology,mechanical properties,and rheology

In this study, polyamide‐66/poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PA66/PPO) blends with high viscosity ratio were processed by a self‐designed triangle‐arrayed triple‐screw extruder (TTSE, which simulates extensional flow) and a commercial twin‐screw extruder (TSE), respectively. Furthermore, in order to improve the mechanical properties of the immiscible PA66/PPO blends, PPO‐grafted maleic anhydride (PPO‐g‐MA) and styrene–ethylene–butylene–styrene (SEBS) block copolymer were used. The mechanical properties, phase morphology, and rheological properties of both binary PA66/PPO blends and toughened PA66/PPO/PPO‐g‐MA blends were comprehensively investigated to compare the above mentioned two processing method. Samples processed with TTSE exhibited better mechanical properties than the TSE‐processed blends. The morphologies of the blends were examined by scanning electron microscopy, exhibiting smaller particles sizes and narrower particle size distributions, which were attributed to the significant effects of extensional flow in TTSE. The toughening mechanism of compatibilized blends was investigated through morphology analysis, dynamic mechanical, and rhelogical analysis. Thus, TTSE with an extensional effect was proved to be efficient in the blending of high viscosity ratio polymers. POLYM. ENG. SCI., 57:1090–1098, 2017. © 2016 Society of Plastics Engineers     

Thermal,mechanical, and morphological characterization studies of poly(2,6‐dimethyl‐1,4‐phenylene oxide) blends with polystyrene and brominated polystyrene

The miscibility of the binary and ternary blends of poly(2,6‐dimethyl‐1,4‐phenylene oxide), brominated polystyrene, and polystyrene was investigated using a differential scanning calorimeter. The morphology of these blends was characterized by scanning electron microscopy. These studies revealed a close relation between the blend structure and its mechanical properties. The compatibilizing effect of poly(2,6‐dimethyl‐1,4‐phenylene oxide) on the miscibility of the polystyrene/brominated polystyrene blends was examined. It was found that poly(2,6‐dimethyl‐1,4‐phenylene oxide), which was miscible with polystyrene and partially miscible with brominated polystyrene, compatibilizes these two immiscible polymers if its contention exceeds 33 wt %. Upon the addition of poly(2,6‐dimethyl‐1,4‐phenylene oxide) to the immiscible blends of polystyrene/brominated polystyrene, we observed a change in the morphology of the mixtures. An improvement in the mechanical properties was noticed. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 225–231, 2000     

Miscibility and specific interactions in blends of poly(vinyl phenyl ketone hydrogenated) with poly(2,6‐dimethyl‐1,4‐phenylene oxide)

The miscibility behavior of poly(vinyl phenyl ketone hydrogenated) (PVPhKH) and poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) are studied by differential scanning calorimetry, thermomechanical analysis, and FTIR spectroscopy. Two miscibility windows between 10 to 40 and 60 to 90 wt % PPO are detected. Only the blend with 50 wt % PPO is immiscible. The best fit of the Gordon–Taylor equation of the experimental glass‐transition temperatures for miscible PVPhKH/PPO blends is shown. A study by FTIR spectroscopy suggests that hydrogen bonding interactions are formed between the hydroxyl groups of PVPhKH and the ether groups of PPO. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1887–1892, 2004     

Compatibilization and toughening of poly(2,6‐dimethyl‐1,4‐phenylene oxide)/polyamide 6 alloy with poly(ethylene 1‐octene): Mechanical properties,morphology, and rheology

Blends of a poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO)/polyamide 6 (PA 6) alloy toughened with a novel polyolefin elastomer poly(ethylene‐1‐octene) (POE) were prepared via melt extrusion. In order to improve the compatibilization between POE and the PPO/PA 6 alloy, POE was grafted with maleic anhydride (MA), which could react with the amine group of PA 6. The Izod impact strength of the blends exhibited an optimum when the extent of MA grafting of POE was changed, which is an order of magnitude higher than that of the untoughened blends. The morphology revealed that the size of the POE particles decreased with an increasing MA grafting ratio of POE. Studies on the tensile properties and rheology of the blends were also carried out. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3110–3116, 2003     

Properties and radiation resistance of aromatic polymer-based polyblends

Blends of either of two different poly(phenylene oxide) (PPO) derivatives with poly(2-vinylnaphthalene) (P2VN) were prepared by casting from chloroform. The content of P2VN in the blends ranged from 0 to 25 wt % for each PPO derivative. Two kinds of PPO derivatives, p–t-butylbenzoyl poly(phenylene oxide) (p–t-BB-PPO) and benzoyl poly(phenylene oxide) (B-PPO), were used. The effects of the addition of P2VN to PPO derivatives were investigated by their thermal stability, light-resistance, and tensile properties. Even though the addition of P2VN to the PPO derivatives decrease the mechanical properties, the radiation resistance was improved. The radiation resistance and tensile properties of B-PPO and its blends with P2VN were higher than those of the p–t-BB-PPO and its blends with P2VN. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1697–1705, 1999     

High‐performance hyperbranched poly(phenylene oxide) modified bismaleimide resin with high thermal stability,low dielectric constant and loss

High‐performance hyperbranched poly(phenylene oxide)‐modified bismaleimide resin with high thermal stability, low dielectric constant, and loss was developed, which is made up of hyperbranched poly(phenylene oxide) (HBPPO), 4,4′‐bismaleimidodiphenylmethane (BDM), and o, o′‐diallylbisphenol A (DBA). The curing reactivity, morphology, and performance of BDM/DBA/HBPPO resin were systemically investigated, and similar investigations for BDM/DBA resin were also carried out for comparison. Results show that BDM/DBA/HBPPO and BDM/DBA resins have similar curing mechanism, but the former can be cured at lower temperature than the later; in addition, cured BDM/DBA/HBPPO resin with suitable HBPPO content has better thermal stability and dielectric properties (lower dielectric constant and loss) than BDM/DBA resin. The difference in macroproperties between BDM/DBA/HBPPO and BDM/DBA resins results from the different chemical structures and morphologies of their crosslinking networks. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Properties and origins of high‐performance poly(phenylene oxide)/cyanate ester resins for high‐frequency copper‐clad laminates

A high‐performance matrix is the key base for the fabrication of high‐frequency copper‐clad laminates. A high‐performance resin system based on commercial poly(phenylene oxide) (PPO) and 2,2′‐bis(4‐cyanatophenyl) isopropylidene (BADCy), coded as PPO‐n/BADCy (where n is the weight parts of PPO per 100 weight parts of BADCy), was developed. The effect of PPO on the key properties, including the dielectric and thermal properties, water resistance, and toughness, of the cured resins was investigated extensively. The results show that PPO not only catalyzed the curing reaction of BADCy but also reacted with BADCy to form a single‐phase structure. Furthermore, compared with the cured BADCy resin with 1 phr epoxy resin as a catalyst, the cured PPO‐n/BADCy resins had significantly increased impact strengths and decreased dielectric constants, loss, and water resistance. The reasons behind these desirable improvements are discussed from the view of structure–property relationships. These results suggest that the PPO‐n/BADCy system has great potential to be used as a matrix for high‐frequency copper‐clad laminates or other advanced composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Relationship between structure and properties in high‐performance PA6/SEBS‐g‐MA/(PPO/PS) blends: The role of PPO and PS

This work aimed at studying the role of poly(phenylene oxide) (PPO) and polystyrene (PS) in toughening polyamide‐6 (PA6)/styrene‐ethylene‐butadiene‐styrene block copolymer grafted with maleic anhydride (SEBS‐g‐MA) blends. The effects of weight ratio and content of PPO/PS on the morphology and mechanical behaviors of PA6/SEBS‐g‐MA/(PPO/PS) blends were studied by scanning electron microscope and mechanical tests. Driving by the interfacial tension and the spreading coefficient, the “core–shell” particles formed by PPO/PS (core) and SEBS‐g‐MA (shell) played the key role in toughening the PA6 blends. As PS improved the distribution of the “core–shell” particles due to its low viscosity, and PPO guaranteed the entanglement density of the PPO/PS phase, the 3/1 weight ratio of PPO/PS supplied the blends optimal mechanical properties. Within certain range, the increased content of PPO/PS could supply more efficient toughening particles and bring better mechanical properties. Thus, by adjusting the weight ratio and content of PPO and PS, the PA6/SEBS‐g‐MA/(PPO/PS) blends with excellent impact strength, high tensile strength, and good heat deflection temperature were obtained. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45281.     

Self‐condensing atom transfer radical polymerization of inimers of different reactivity ratios with styrene and the thermal properties of poly(2,6‐dimethyl‐1, 4‐phenylene oxide)/branched polystyrene blends

Although the self‐condensing atom transfer radical polymerization (SCATRP) of inimers with typical comonomers has been extensively performed, there have been few reports to correlate the reactivity ratio with the growth of the molecular weights (MWs) and the development of branched structures. Thus, the SCATRP of inimers of different reactivity ratios, namely, 4‐chloromethylstyrene (CMS) and maleimide (MI) inimers, with a large excess of styrene (St) were carried out, respectively, to examine the effect. The conversion and MW were monitored by gas chromatography, gel permeation chromatography, and multiangle laser light scattering. The results suggested that CMS merely functioned as an initiator for St at the early stage; this led to linear macroinimers, which underwent SCATRP and gave rise to randomly branched polystyrene (PS) only at high conversion. The MI inimers formed charge‐transfer complexes with St and underwent the SCATRP to result in hyperbranched copolymers at first; this initiated the atom transfer radical polymerization of St and led to star‐shaped PS. With the objective of improving the processability and melt fluidity, the physical properties of poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) blends with linear, randomly branched, and star‐shaped PS were compared. In comparison with those with linear PS, the PPO/branched PS blends exhibited a higher glass‐transition temperature, a higher melt flow index, and a comparable thermal stability because of the spherical architecture of the branched PS. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Compatibilization of PPO/LCP blends by semi‐interpenetrating liquid crystalline polymer networks LCP/PS

A new approach for enhancing the compatibility of liquid crystalline polymers (LCPs) with engineering thermoplastics is developed in this paper. By adding a new type of compatibilizer to poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO)/LCP blends (semi‐interpenetrating LCP network (ILCPN) comprising the liquid crystalline polymer poly‐(ethylene terephthalate)/p‐hydroxybenzoic acid (PET/60PHB) and crosslinked polystyrene), a well‐compatibilized PPO/LCP composite with considerably improved mechanical properties was obtained. Compared with the uncompatibilized PPO/LCP blend, the bending strength and the Izod impact strength of the compatibilized sample with 5% semi‐ILCPN increase more than 2 and 4 times, respectively.     

Blends of polyamide 6, polycarbonate,and poly(propylene oxide). II. Reactive compatibilization–thermal degradation relationships

The thermal degradation of some blends of polyamide 6/polycarbonate (PA6/PC) and polyamide 6/polycarbonate/poly(propylene oxide) (PA6/PC/PPO) were investigated. The copolymer formed during the mixing of polyamide 6 and polycarbonate, at 240°C, for 30 min, increases the thermal stability of PA6/PC and of PA6/PC/PPO blends. This increase in the thermal stability occurs due to the plasticizing effect of PPO, which increases the mobility of the molecules of PA6 and PC, and consequently increases the probability of the reaction between the —NH₂ and —O—CO—O groups of polyamide 6 and polycarbonate, respectively. The ternary blends with PPO (5–10% w/w) have lower thermal stability than PA6/PC blends. This is due to the decrease of miscibility between these polymers and the rise of the diluting effect. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2556–2562, 2001     

The preparation of microporous membranes from blends of poly(2,6‐dimethyl‐1,4‐phenylene oxide) and sulfonated poly(2,6‐dimethyl‐1,4‐phenylene oxide)

Poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) is a chemically resistant polymer and, therefore, an attractive material for the formation of membranes. However, membranes of unmodified PPO prepared by an immersion precipitation possess very low hydraulic permeabilities at the filtration processes. The membranes with higher hydraulic permeabilities can be prepared from sulfonated PPO and/or from blends of unsulfonated PPO and sulfonated PPO. In conclusion, the mechanism of the formation of membranes from blends of unsulfonated PPO and sulfonated PPO is suggested. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 161–167, 1999     

Relation between strain hardening and wear resistance of polymers

The friction and abrasive wear of blends of polystyrene (PS) and poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) were measured. The coefficient of friction decreases only slightly with an increasing PPO fraction, while the abrasive wear decreases largely upon the introduction of increasing amounts of PPO. It is clearly shown that the abrasive wear resistance of the PS/PPO blends increases with an increasing strain hardening modulus of the blend. The wear rate change between 20 and 40 wt % PPO is ascribed to a transition in the failure mechanism from predominantly brittle to predominantly tough. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2689–2692, 2004