Wood-fiber reinforcement of styrene–maleic anhydride copolymers

Styrene–maleic anhydride (SMA) copolymers containing either 7 or 14% maleic anhydride were filled with either pine flour or dry-process aspen fiber from a medium density fiberboard (MDF) plant. Material properties of the filled and unfilled SMA plastics were compared with those of aspen-fiber-filled and unfilled polystyrene (PS). The fiber-filled SMA composites were equivalent or superior to unfilled SMA in strength, stiffness, and notched Izod impact strength. Filled PS composites outperformed or matched the performance of filled SMA composites in the parameters tested. Unnotched Izod impact strength of filled polymers was generally inferior to that of the unfilled polymers. Water absorption from a 90% relative humidity exposure, a 24-h soak, and a 2-h boil showed mixed results when compared to the unfilled polymers. Dynamic mechanical analysis showed no change in glass transition temperature (T_g) after the addition of filler for either SMA or PS composites. The presence of the anhydride functionality on the polymer backbone did not appear to improve the strength of the composite. No evidence was found for chemical bond formation between the SMA and wood fiber. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1567–1573, 1998     

Functional polymers for colloidal applications. X. Syntheses of graft-charged naphthalene–formaldehyde condensates and their ability to disperse dyes

N-(3-sodium propylsulfonate)-α-naphthylamine–formaldehyde condensates (NAFS) and O-(3-propylsulfonate)-α-naphthol–formaldehyde condensates (NOFS) are synthesized by condensation reactions followed by ring-opening reactions. Those condensates are used as dispersants to disperse dyes in water (C. I. Navy Blue 79 and C. I. Brown 1), and can be compared to the conventional dispersants [e.g., naphthalenesulfonate–formaldehyde condensates (NSF)]. The dispersing properties of the condensates were evaluated by scanning electron microscopy (SEM), sedimentation, as well as measurments of viscosity. For NAFS or NOFS, the sulfonate groups were grafted separately on the backbone of the condensate; however, for NSF, the sulfonate groups were anchored on the backbone of the condensate. The structural effects of those condensates were demonstrated by comparing the dispersing ability of these condensates, and the conventional condensates NAFS and NOFS exhibit better dispersing abilities than NSF for the Navy Blue 79 and Brown 1 dyes. © 1996 John Wiley & Sons, Inc.     

Blends of bisphenol A polycarbonate and rubber‐toughened styrene–maleic anhydride copolymers

The morphology and mechanical properties of polycarbonate (PC) blends with rubber‐toughened styrene–maleic anhydride copolymer materials (TSMA) were investigated and compared with the properties of blends of PC with acrylonitrile–butadiene–styrene (ABS) materials. The PC/TSMA blends showed similar composition dependence of properties as the comparable PC/ABS blends. Polycarbonate blends with TSMA exhibited higher notched Izod impact toughness than pure PC under sharp‐notched conditions but the improvements are somewhat less than observed for similar blends with ABS. Since PC is known for its impact toughness except under sharp‐notched conditions, this represents a significant advantage of the rubber‐modified blends. PC blends with styrene–maleic anhydride copolymer (SMA) were compared to those with a styrene–acrylonitrile copolymer (SAN). The trends in blend morphology and mechanical properties were found to be qualitatively similar for the two types of copolymers. PC/SMA blends are nearly transparent or slightly pearlescent. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1508–1515, 1999     

Polymer blends with modified coupling agent. I. Preparation and thermal properties of LICA 44 grafted styrene–maleic anhydride copolymer

Neopentyl(diallyl)oxy, tri(N-ethyleneamino)ethyl titanate (LICA 44) was grafted to the styrene/maleic anhydride (SMA) copolymer for the purpose of obtaining a new interfacial coupling agent for flame retardant ABS blends. The graft reaction was proceeded in DMSO under 80°C and reduced pressure. Samples were prepared under various amine/anhydride ratios (AAR) in feed and reaction time. The verification of reaction was based on FTIR spectra and the results of elemental analysis. The reaction percentages were high but decreased with the rising AAR. Both combination types, amide acid and imide, of SMA and LICA 44 were found, and the ratio of amide acid and imide is related to the AAR and reaction time. After the graft reaction, both the initial pyrolysis temperature (T_pi) and the char yield at 800°C of SMA increased significantly. LICA 44 is believed to cause the char promoting effect on SMA-g-L44. And the dealcohol phenomenon of trimethylolpropane diallyl ether (TMPDE) away from SMA-g-L44 was observed during the thermal analysis. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68:37–44, 1998     

Functional polymers for colloidal application. VIII. Syntheses of anionic and zwitterionic aniline–formaldehyde condensates and their dispersing ability to zwitterionic clay

Anionic and zwitterionic aniline–formaldehyde condensates have been synthesized by a methylenation under mild reaction conditions and a reaction with propane sultone. The formation of condensates is characterized by NMR, i.e., the peak of methylene at δ = 3.5?4.0 ppm and the peaks of propylsulfonate at δ = 2.7?3.4 ppm and δ = 1.7?2.2 ppm. The results from GPC show that a longer condensation time increases the degree of polymerization of the condensates. The dispersing properties of the condensates are assessed by the viscosity, scanning electron microscopy (SEM), and adsorption behaviors. N,N-dimethyl-N-(3-propylsulfonate) anilinium–formaldehyde condensates (DPSAF) with higher molecular weight (DPSAF-H) show significantly lower apparent viscosities. Comparing the results of SEM and the viscosity method, it can be concluded that, under comparable conditions, a suspension with a lower viscosity is more homogeneously dispersed. The amount of DPSAF-H adsorbed onto clay is significantly higher than that of PSAF-H at low concentrations of the dispersant and reaches an optimum after ca. 3 wt %. This result is in parallel with the trend of viscosity. The zwittionic DPSAF promotes their dispersing ability of clay in water due to the existence of the positive and negative charges. The decrease in the amount of adsorbed PSAF-H with increasing pH can be interpreted by the increased negative charge of the clay, as a result of the decreased interaction between the anionic PSAF-H and the clay. © 1993 John Wiley & Sons, Inc.     

Functional polymers for colloidal applications (III): Structural effects of lipophile-modified styrene-maleic anhydride copolymers on dispersing polar and nonpolar particles

Styrene-maleic anhydride copolymer (SMA) with the molecular weight (MW: 7100) suitable for acting as a dispersant was synthesized and then ring-opened with alkylamine to prepare the n-butyl and n-dodecyl-substituted SMA. The prepared lipophile-modified SMA copolymers were used as dispersants to disperse both polar and nonpolar particles (TiO₂ and carbon black). Upon dispersing TiO₂ and carbon black, the antibridging effect (a larger optimum concentration and a less sharp increase after optimum concentration) was observed for SMA as well as n-butylamide-substituted SMA as compared to sodium polyacrylate. The bridging effect, however, is obvious for n-dodecylamide highly substituted SMA (12N45). For dispersing TiO₂, both for n-butyl and n-dodecylamide-substituted SMA, the curve of viscosity vs. concentration increases less sharply after optimum concentration except for 12N45. In the case of dispersing carbon black, the n-butylamide-substituted SMA shows a pronounced antibridging effect, while the n-dodecylamide-substituted SMA shows a significant bridging effect. The minimum viscosity and the optimum concentration for both n-butyl and n-dodecylamide-substituted SMA are correlated to conclude that: (a) at low percentage of alkylamide in SMA, both for n-butyl and n-dodecyl group cause bridging phenomena and increase the viscosity; (b) as the percentage of alkylamide in SMA increase, the adsorption effect is more important for n-butylamide-substituted SMA (e.g., 4N45), and the bridging effect is more important for n-dodecylamide-substituted SMA (e.g., 12N45); (c) the decrease in optimum concentration for 12N45 can be interpreted by the bridging effect.     

Functional polymers for colloidal application. VI. Syntheses and dispersing ability of lipomodified naphthalenesulfonate formaldehyde condensates

Butyl-substituted naphthalenesulfonate formaldehyde condensates (C4NSF) with different molecular weights were synthesized. The structures were confirmed by NMR in terms of the appearance of the signal at δ = 3.3–4.0 ppm, and the molecular weights of the synthesized C4NSFs were compared by gel permeation chromatography (GPC). C4NSFs used as dispersants were compared to unmodified naphthalenesulfonate formaldehyde condensates (NSF) in their ability to disperse nonpolar particles (carbon black) and polar particles (TiO₂) in water. Their dispersing ability was evaluated by both a viscosity method and a microscopy method. For dispersing carbon black in water, it was found that using C4NSFs as dispersing agents results in a lower viscosity, a lower yield value by the viscosity method, and a more homogeneous dispersion of particles as determined by microscopy. These results indicate that the butyl group enhances the dispersing ability of C4NSF. The effect of the butyl group on the dispersing ability of C4NSF was interpreted by the results of the measured adsorption amount that was also enhanced by the existence of the butyl group. For dispersing TiO₂ in water, C4NSF results in a higher viscosity and a higher adsorption amount of the dispersed system than NSF. These phenomena were interpreted in terms of the hydrophobic interaction between the butyl groups and the bridging effect. © 1993 John Wiley & Sons, Inc.     

Porous structure and swelling properties of styrene–divinylbenzene copolymers for size exclusion chromatography

Small spherical particles of styrene–divinylbenzene copolymers have been synthesized by modified suspension polymerization. The effects of divinylbenzene (DVB) contents, dilution degree of the monomers and diluent composition on the porous structure and swelling properties of the copolymers were investigated. Toluene uptakes of macroporous copolymers were considered as a result of three contributions: filling of the fixed pores, expansion of the fixed or collapsed pores, and nuclei swelling and heptane uptakes as a result of the two first contributions. The increase of DVB content in the copolymers synthesized in presence of a solvating diluent (toluene) provoked a decrease on the nuclei swelling. The increase of dilution degree with solvating diluents changed the toluene and heptane uptakes, and when the diluent–copolymer affinity was reduced, the fixed pore volume increased. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1257–1262, 1997     

Synthesis of polyurethane–imide (PU–imide) copolymers with different dianhydrides and their properties

This study reports the synthesis of polyurethane–imide (PU–imide) copolymers using 4,4′-diphenylmethane diisocyanate (MDI) polytetramethylene glycols (PTMGs) and different aromatic dianhydrides. Differential scanning calorimetry (DSC) results indicate that PU–imide copolymers had two phase structures containing four transition temperatures (T_gs, T_ms, T_gh and T_mh). However, only PU–imide copolymers were formed by soft PTMG(2000) segments possessing a T_ms (melting point of soft segment). When different aromatic dianhydrides were introduced into the backbone chain of the polyurethane, although the T_gs (glass transition temperature of the soft segment) of some of PU–imide copolymers did not change, the copolymers with long soft segments had low T_gs values. The T_gh (glass transition temperature of hard segment) values of PU–imide copolymers were higher than that of polyurethane (PU). In addition, the high hard segment content of PU–imide copolymer series also had an obvious T_mh (melting point of hard segment). According to thermogravimetric analysis (TGA) and differential thermogravimetric analysis (DTGA), the PU–imide copolymers had at least two stages of degradation. Although the T_di (initial temperature of degradation) depended on the hard segment content and the composition of hard segment, the different soft segment lengths did not obviously influence the T_di. However, PU–imide copolymers with a longer soft segment had a higher thermal stability in the degradation temperature range of middle weight loss (about T_d 5%–50%). However, beyond T_d 50% (50% weight loss at temperature of degradation), the temperature of degradation of PU–imide copolymers increased with increasing hard segment content. Mechanical properties revealed that the modulus and tensile strength of PU–imide copolymers surpassed those of PU. Wide angle X-ray diffraction patterns demonstrated that PU–imide copolymers are crystallizable. © 1999 Society of Chemical Industry     

Functional polymers for colloidal applications. I. Structural effects of lipophile-modified polyacrylates on adsorption and dispersion ability

Polyacrylic acids of four molecular weights are prepared. A series of poly(methylacrylate-acrylic acid) copolymers with four specific methylacrylate/acrylic acid ratios and molecular weights has been successfully synthesized from the corresponding polyacrylic acids. These polymers and copolymers are used as dispersants for dispersing TiO₂ into aqueous phase. Viscosity, sedimentation, and electron microscopy are used to evaluate their dispersion ability. The extent of adsorption and the zeta potential are measured to evaluate their adsorption behaviors on the surface of TiO₂. The viscosity, sedimentation, and electron microscopy results are comparable parallel for showing the dispersing ability of a polymer or a copolymer. The polymer (or copolymer), which results in a lower viscosity, shows a slower sedimentation rate and a more homogeneous distribution of particles in microphotographs. The minimum viscosity needed to disperse TiO₂ decreases with the decreasing molecular weight of polyacrylic acid. It was found that partial esterification of polyacrylic acid results in a broader range of minimum viscosity. The trend of the amount adsorbed is similar to that of zeta potential. These two results are used to interpret the viscosity curve.     

Functional polymers for colloidal applications. II. Hydrophobic effects of polyacrylic copolymer on dispersing polar and nonpolar particles

The polyacrylic acids with fixed molecular weights are specifically esterified by lauryl alcohol and methyl alcohol to prepare copolymers. These copolymers are used as dispersants for dispersing TiO₂ and carbon black. It was found that lauryl-esterified copolymers decrease the minimum viscosity and optimum concentrations both for TiO₂ and carbon black due to strong hydrophobic interactions. However, the methyl esterified polyacrylic acid significantly broadens the range of optimum concentrations due to the interruption of polymer interactions between particles by methyl groups. Four different dispersion systems (LB/carbon black, LB/TiO₂, MB/carbon black, and MB/TiO₂) are used. These results are discussed and correlated to the structure of dispersant. The bridging effect of esterified lauryl group and the antibridging effect of esterified methyl group are used tó interpre the viscosity phenoma of those dispered systems.     

Substituted styrenes–maleic anhydride copolymers—Measurements of the reactivity ratios with high conversions and relations between molecular masses and viscosity

Three substituted styrenes were respectively synthesized by reaction of benzoic acid, acetic acid, and methanol with vinylbenzylchloride, then copolymerized with maleic anhydride. The measurements of the reactivity ratios of these three copolymerizations were carried out with a method using high conversions of the reactions. The results show a good correlation between a linear alternating structure for one of the copolymers and an alternating and a partially crosslinked structure for the two others. The copolymerizations were also performed with various percentages of initiator, giving similar proportions of incorporated monomers in the resulting products, and a relation between their viscosities and their weight molecular masses was presented. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1447–1454, 1999     

Polymer blends with modified coupling agent. II. Effects of LICA 44 grafted styrene–maleic anhydride copolymer on properties of flame retardant acrylonitrile–butadiene–styrene blends

Flame retardant acrylonitrile–butadiene–styrene (FR‐ABS) blends were prepared by blending tetrabromobisphenol A (TBBA) and antimony trioxide (Sb₂O₃) into the ABS resin. LICA 44 grafted styrene–maleic anhydride (SMA‐g‐L44) copolymers were used as high molecular weight (MW) coupling agents to modify the properties of the FR‐ABS blends, and the copolymers with different LICA 44 grafting ratios were produced via the in vivo and the in situ reactions, respectively. The LICA 44 percentage and the MW of the SMA‐g‐L44 copolymers are important factors influencing the effects of the high MW coupling agent. The impact strength and the tensile yield stress of SMA‐g‐L44 modified FR‐ABS blends increased obviously. The elongation at break and the limiting oxygen index of which also showed an increasing trend after the modification. The coupling effect of SMA‐g‐L44 became weaker at a higher grafting ratio. SEM observation showed that the interfacial boundary in the FR‐ABS became fuzzy after using the SMA‐g‐L44 copolymers. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 865–874, 1999     

Functional polymers for colloidal application. IX. The dispersing ability of anionic and zwitterionic aniline-formaldehyde condensates to dyes

Anionic and zwitterionic aniline–formaldehyde condensates, N-(3-sodium propylsulfonate) aniline–formaldehyde condensates (PSAF), and N, N-dimethyl-N-(3-propylsulfonate) anilinium–formaldehyde condensates (DPSAF) are used as dispersants to disperse dyes (C. I. Navy Blue 79 and C. I. Brown 1), compared with the conventional dye dispersants–naphthalenesulfonate formaldehyde condensates (NSF). The dispersing properties of the condensates are assessed by the viscosity method, scanning electron microscopy (SEM), the final volume fraction after sedimentation, and adsorption behaviors. Compared to DPSAF, the PSAF and NSF with a lower molecular weight (PSAF-L, NSF-L) show significantly lower apparent viscosities of the paste of Navy Blue 79. Comparing the results of the viscosity method with those of SEM and the final volume fraction after sedimentation, it can be concluded that a better-dispersed paste displayed by SEM shows a lower viscosity and a smaller final volume fraction. The amount of NSF-L adsorbed on Navy Blue 79 is significantly higher than that of PSAF-L and DPSAF-H. However, the sulfonate on PSAF-L can be extended more deeply toward the bulk phase compared to that on NSF-L so that PSAF-L can result in a high effective thickness. These adsorption phenomena are used to interpret the dispersing ability. For Brown 1, the anionic dispersants can reach a similar minimum viscosity independent of their molecular weight, but the PSAF with high molecular weight shows a remarkably low optimum concentration (ca. 3% compared to PSAF-L 9%, NSFs 5%). © 1993 John Wiley & Sons, Inc.     

Core–shell particles to toughen epoxy resins. I. Preparation and characterization of core–shell particles

A two-stage, multistep soapless emulsion polymerization was employed to prepare various sizes of reactive core–shell particles (CSPs) with butyl acrylate (BA) as the core and methyl methacrylate (MMA) copolymerizing with various concentrations of glycidyl methacrylate (GMA) as the shell. Ethylene glycol dimethacrylate (EGDMA) was used to crosslink either the core or shell. The number of epoxy groups in a particle of the prepared CSP measured by chemical titration was close to the calculated value based on the assumption that the added GMA participated in the entire polymerization unless it was higher than 29 mol %. Similar results were also found for their solid-state ^13C-NMR spectroscopy. The MMA/GMA copolymerized and EGDMA-crosslinked shell of the CSP had a maximum glass transition temperature (T_g) of 140°C, which was decreased with the content of GMA at a rate of −1°C/mol %. However, the shell without crosslinking had a maximum T_g of 127°C, which decreased at a rate of −0.83°C/mol %. The T_g of the interphasial region between the core and shell was 65°C, which was invariant with the design variables. The T_g of the BA core was −43°C, but it could be increased to −35°C by crosslinking with EGDMA. The T_g values of the core and shell were also invariant with the size of the CSP. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2069–2078, 1998     

The effect of polymers on the crystallisation of n-alkanes from solution,part 1. Preparation and investigation of spin-labelled fumarate–vinyl acetate copolymers

Spin-labelled fumarate-vinyl acetate (FVA) copolymers with octyl (C₈) and octadecyl (C₁₈) ester groups were prepared and characterised. An interaction between the C₁₈FVA and the developing crystals of n-dotriacontane growing from dodecane solution was observed as a slow-motion component in the electron spin resonace (ESR) spectrum of the system. The C₈FVA showed no such behaviour, the spectrum being entirely of the motionally narrowed type through out the crystallisation process. Above the cloud point of the system, no interaction between the polymer and alkane could be detected either in the ESR spectra or from measurements of the rotational correlation times of the spinlabel nitroxide.     

Studies of crosslinked styrene–alkyl acrylate copolymers for oil absorbency application. I. Synthesis and characterization

The prepolymers for a novel oil absorbent were synthesized by copolymerizing styrene with 2‐ethylhexyl acrylate (EHA), lauryl acrylate (LA), lauryl methacrylate (LMA), and stearyl acrylate (SA). Suspension polymerization was carried out using benzoyl peroxide (BPO) as an initiator with a varying monomer feed ratio, and the copolymers were characterized by FTIR, ¹H‐NMR, DSC, and a solubility test. The copolymers were random copolymers with a single phase, and their compositions were similar to those in the monomer feed. The T_g of the copolymer could be controlled by varying the styrene/acrylate ratio. Acrylates introduced the crosslinking to linear polymers as a side reaction. Crosslinked copolymers were synthesized by adding divinylbenzene (DVB) as a crosslinking agent. At a low degree of crosslinking (0.5 wt % DVB), the T_g of the crosslinked copolymers was lower than or similar to that of the uncrosslinked ones. At a high degree of crosslinking, the T_g increased with increasing crosslinking density. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 903–913, 2000     

Synthesis of PP–LCP graft copolymers and their compatibilizing activity for PP/LCP blends

The aim of this work was the synthesis of new graft copolymers consisting of polypropylene (PP) backbones and liquid crystalline polymer (LCP) branches, to be used as compatibilizing agents for PP/LCP blends. The PP-g-LCP copolymers have been prepared by polycondensation of the monomers of a semiflexible liquid crystalline polyester (SBH 1 : 1 : 2), that is, sebacic acid (S), 4,4′-dihydroxybiphenyl (B), and 4-hydroxybenzoic acid (H) in the mole ratio of 1 : 1 : 2, carried out in the presence of appropriate amounts of a commercial acrylic-acid-functionalized polypropylene (PPAA). The polycondensation products, referred to as COPP50 and COPP70, having a calculated PPAA concentration of 50 and 70 wt %, respectively, have been fractionated with boiling toluene and xylene, and the soluble and insoluble fractions have been characterized by Fourier transform infrared and nuclear magnetic resonance spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry, and X-ray diffraction. All analytical characterizations have concordantly shown that the products are formed by intricate mixtures of unreacted PPAA and SBH together with PP-g-SBH copolymers of different composition. Exploratory experiments carried out by adding small amounts of COPP50 or COPP70 into binary mixtures of isotactic polypropylene (iPP) and SBH while blending have demonstrated that this practice leads to an appreciable improvement of the dispersion of the minor LCP phase, as well as to an increase of the crystallization rate of iPP. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 391–403, 1998     

Synthesis and characterization of styrene–divinylbenzene loaded with di(2-ethylhexyl)phosphonic acid. I. Influence of diluent mixture on the porous structure of the copolymer

Styrene–divinylbenzene copolymers were synthesized in the presence of di(2-ethylhexyl)phosphonic acid (EHEHPA) to be applied in the separation of rare earths by extraction chromatography. The copolymers were prepared by suspension polymerization in the presence of pure EHEHPA or in a mixture with isooctane, heptane, or toluene. The composition of the diluent mixture employed in the synthesis was varied. The apparent density, fixed pore volume, and surface area of the copolymers were determined. The content of EHEHPA retained in the copolymer beads was also determined, and it was found to be independent of the porous structure of the copolymer matrix. That content was only dependent on the amount of EHEHPA present in the diluent mixture. The toluene/EHEHPA mixtures produced the copolymers with the best properties required for extraction chromatography supports. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:781–787, 1998     

New perfectly difunctional organolithium initiators for block copolymer synthesis: 2. Difunctional polymers of dienes and of their triblocks copolymers with styrene

New organodilithium initiators were prepared in a hydrocarbon solvent in the absence of any polar additive. Although these initiators are insoluble when they are synthesized, they may be easily purified and reacted with dienes to give perfectly telechelic polydienes having unimodal distributions and low dispersity. A good agreement between experimental and theoretical molecular weights was observed. The polymer microstructures were similar to those of polymers initiated by butyllithium in the same solvent. Triblock thermoplastic elastomers were also prepared, the characteristics of which are given. The mechanical properties of a S.B.S. sample support also the claim of a good initiating ability and difunctionality of these initiators.