Binary Blends Of Poly Research Articles

Morphology and pH Sensing Characteristics of New Luminescent Electrospun Fibers Prepared from Poly(phenylquinoline)‐block‐Polystyrene/Polystyrene Blends

New luminescent electrospun (ES) fibers for pH-tunable colorimetric sensors were prepared from binary blends of poly(phenylquinoline)-block-polystyrene (PPQ-b-PS)/polystyrene (PS) with a single-capillary spinneret. The PPQ-b-PS aggregated domain sizes in the ES fibers prepared from dichloromethane (CH(2) Cl(2) ), chlorobenzene (CB) and chloroform (CHCl(3) ) were 1.5 ± 0.5, 2.2 ± 0.4 and 4.1 ± 1.1 µm, respectively. Such variation on the aggregation size led to the red-shifting photoluminescence spectra changing from green, to yellow, and orange. ES fibers prepared from CH(2) Cl(2) exhibited pH-tunable photoluminescence and the emission maximum varied from 532 to 560 nm as the pH value changed from 7 to 1. The study demonstrated that the ES fibers prepared could have potential applications for sensory devices.

UCST-Type Phase Separation and Crystallization Behavior in Poly(vinylidene fluoride)/Poly(methyl methacrylate) Blends under an External Electric Field

The effects of an electric field on upper critical solution temperature (UCST) phase separation and crystallization behavior in binary blends of poly(vinylidene fluoride) (PVDF) and poly(methyl methacrylate) (PMMA) were investigated by means of time-resolved small-angle light scattering (SALS) and polarizing optical microscopy (POM). The lower critical solution temperature (LCST) phase separation curve of this blend could not be measured experimentally due to thermal decomposition caused by too high LCSTs. However, the UCST-type phase separation curve was observed from SALS measurements to shift toward higher temperatures under the electric field. In the temperature range above the UCST (150 °C ≤ T ≤ 158 °C), the electric field reduces the overall crystallization rate in the neat PVDF and, in contrast, increases the crystallization rate in 95/5, 90/10, and 85/15 PVDF/PMMA blends. In the temperature range below the UCST (130 °C ≤ T ≤ 143 °C), the electric field also increased the overall crystallization rate in the 80/20 and 70/30 PVDF/PMMA blends. POM images were also used to investigate the effect of the electric field on the overall melt-crystallization rate, nucleation rate, and crystalline morphology in PVDF/PMMA blends.

Non-isothermal crystallization of PET/PLA blends

Binary blends of poly(ethylene terephthalate) with poly(lactic acid), PET/PLA, were studied by differential scanning calorimetry and X-ray scattering. The PET/PLA blends, prepared by solution casting, were found to be miscible in the melt over the entire composition range. Both quenched amorphous and semicrystalline blends exhibit a single, composition dependent glass transition temperature. We report the non-isothermal crystallization of (a) PET, with and without the presence of PLA crystals and (b) PLA, with and without the presence of PET crystals. PET can crystallize in all blends, regardless of whether PLA is amorphous or crystalline, and degree of crystallinity of PET decreases as PLA content increases. In contrast, PLA crystallization is strongly affected by the mobility of the PET fraction. When PET is wholly amorphous, PLA can crystallize even in 70/30 blends, albeit weakly. But when PET is crystalline, PLA cannot crystallize when its own content drops below 0.90. These different behaviors may possibly be related to the tendency of each polymer to form constrained chains, i.e., to form the rigid amorphous fraction, or RAF. PET is capable of forming a large amount of RAF, whereas relatively smaller amount of RAF forms in PLA. Like the crystals, the rigid amorphous fraction of one polymer component may inhibit the growth of crystals of the other blend partner.

New fluorene–pyrazino[2,3‐g]quinoxaline‐conjugated copolymers: Synthesis, optoelectronic properties, and electroluminescence characteristics

AbstractNew donor–acceptor conjugated copolymers called poly}2,7‐(9,9′‐dihexylfluorene)‐co‐5,10‐[pyrazino(2,3‐g)quinoxaline]{s or PFPQs [where F represents the 2,7‐(9,9′‐dihexylfluorene) moiety and PQ represents the 5,10‐(pyrazino[2,3‐g]quinoxaline) moiety], synthesized by the palladium‐catalyzed Suzuki coupling reaction, are reported. The PQ contents in the PFPQ copolymers were 0.3, 1, 5, and 50 mol %, and the resulting copolymers were named PFPQ0.3, PFPQ01, PFPQ05, and PFPQ50, respectively. Absorption spectra showed a progressive redshift as the PQ acceptor content increased. The relatively small optical band gap of 2.08 eV for PFPQ50 suggested strong intramolecular charge transfer (ICT) between the F and PQ moieties. The photoluminescence emission peaks of the PFPQ copolymer films also exhibited a large redshift with enhanced PQ contents, ranging from 551 nm for PFPQ0.3 to 592 nm for PFPQ50. However, the PFPQ copolymer based electroluminescence (EL) devices showed poor device performances probably due to the strong confinement of the electrons in the PQ moiety or significant ICT. This problem was resolved with a binary blend of poly[2,7‐(9,9‐dihexylfluorene)] (PF) and PFPQ with a volume ratio of 95/5 (BPQ05). Multiple emission peaks were observed at 421, 444, 480, 516, and 567 nm in the BPQ05‐based EL devices because the low PQ content led to incomplete energy transfer. The Commission Internationale de L'Eclairage 1931 coordinates of the BPQ05‐based EL device were (0.31, 0.32), which were very close to the standard white emission of (0.33, 0.33). Furthermore, the maximum luminescence intensity and luminescence yield were 524 cd/m2 and 0.33 cd/A, respectively. This study suggested that a pure white light emission was achieved with the PFPQ copolymers or PF/PFPQ blends through the control of the energy transfer between F and PQ. Such PFPQ copolymers or PF/PFPQ blends would be interesting for electronic and optoelectronic devices. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Mechanical properties of poly(ε‐caprolactone) and poly(lactic acid) blends

AbstractThe aim of this work was to better understand the performance of binary blends of biodegradable aliphatic polyesters to overcome some limitations of the pure polymers (e.g., brittleness, low stiffness, and low toughness). Binary blends of poly(ε‐caprolactone) (PCL) and poly(lactic acid) (PLA) were prepared by melt blending (in a twin‐screw extruder) followed by injection molding. The compositions ranged from pure biodegradable polymers to 25 wt % increments. Morphological characterization was performed with scanning electron microscopy and differential scanning calorimetry. The initial modulus, stress and strain at yield, strain at break, and impact toughness of the biodegradable polymer blends were investigated. The properties were described by models assuming different interfacial behaviors (e.g., good adhesion and no adhesion between the dissimilar materials). The results indicated that PCL behaved as a polymeric plasticizer to PLA and improved the flexibility and ductility of the blends, giving the blends higher impact toughness. The strain at break was effectively improved by the addition of PCL to PLA, and this was followed by a decrease in the stress at break. The two biodegradable polymers were proved to be immiscible but nevertheless showed some degree of adhesion between the two phases. This was also quantified by the mechanical property prediction models, which, in conjunction with material property characterization, allowed unambiguous detection of the interfacial behavior of the polymer blends. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Rheological behavior of polyester blend and mechanical properties of the polypropylene–polyester blend fibers

The article deals with method of preparation, rheological properties, phase structure, and morphology of binary blend of poly(ethylene terephthalate) (PET)/poly(butylene terephthalate) (PBT) and ternary blends of polypropylene (PP)/(PET/PBT). The ternary blend of PET/PBT (PES) containing 30 wt % of PP is used as a final polymer additive (FPA) for blending with PP and subsequent spinning. In addition commercial montane (polyester) wax Licowax E (LiE) was used as a compatibilizer for spinning process enhancement. The PP/PES blend fibers containing 8 wt % of polyester as dispersed phase were prepared in a two-step procedure: preparation of FPA using laboratory twin-screw extruder and spinning of the PP/PES blend fibers after blending PP and FPA, using a laboratory spinning equipment. DSC analysis was used for investigation of the phase structure of the PES components and selected blends. Finally, the mechanical properties of the blend fibers were analyzed. It has been found that viscosity of the PET/PBT blends is strongly influenced by the presence of the major component. In addition, the major component suppresses crystallinity of the minor component phase up to a concentration of 30 wt %. PBT as major component in dispersed PES phase increases viscosity of the PET/PBT blend melts and increases the tensile strength of the PP/PES blend fibers. The impact of the compatibilizer on the uniformity of phase dispersion of PP/PES blend fibers was demonstrated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4222–4227, 2006

Effects of Phase Separation on the Crystallization Behavior in a Binary Blend of Poly(ε-caprolactone) Homopolymer and Poly(ε-caprolactone)-block-Polybutadiene Copolymer

The crystallization process of poly(ε-caprolactone) (PCL) chains in a binary crystalline/crystalline blend, PCL homopolymer and PCL-block-polybutadiene diblock copolymer (PCL-b-PB), has been investigated by synchrotron small-angle X-ray scattering (SR-SAXS) as a function of the characteristic length of composition variation ξ formed by the phase separation between PCL and PCL-b-PB. The temperature range of an UCST-type phase separation overlaps with that of crystallization in this blend, so that the phase separation starts in advance to yield various heterogeneous structures when the blend is quenched from a microphase-separated melt into the crystallization temperature of PCL chains. When ξ<500 nm the crystallization rate of PCL is equal to that of PCL blocks in PCL-b-PB though there is a large difference in the crystallization rate between neat PCL and PCL blocks. When ξ>500 nm, on the other hand, the crystallization rate of PCL deviates significantly from that of PCL blocks, and they approach to the values of neat polymers with increasing ξ. The relation between the crystallization rate and the pre-existing composition heterogeneity is quantitatively discussed.

Synchrotron SAXS Studies on Morphology Formation in a Binary Blend of Poly(ε-caprolactone) Homopolymer and Poly(ε-caprolactone)-block-Polybutadiene Copolymer

The process of morphology formation in a binary blend of poly(ε-caprolactone) homopolymer (PCL) and poly(ε-caprolactone)-block-polybutadiene copolymer (PCL-b-PB) has been investigated by synchrotron small-angle X-ray scattering (SR-SAXS). This blend shows an UCST-type phase separation and the crystallization of PCL chains (i.e., PCL and PCL blocks in PCL-b-PB) at a same temperature range, so that these two factors may work simultaneously to yield a complicated morphology formation. When the weight fraction of PCL (φPCL) is small (φPCL<0.2) or large (φPCL>0.8), the blend can directly be quenched into crystallization temperatures without passing through the UCST region. Time-resolved SAXS curves in this case show that overall morphology formation is driven by the crystallization of PCL chains, where a crystallized PCL region always coexists with a crystallized PCL-b-PB region and the volume ratio of two regions is constant throughout.

Morphology and Field-Effect Mobility of Charge Carriers in Binary Blends of Poly(3-hexylthiophene) with Poly[2-methoxy-5-(2-ethylhexoxy)-1,4-phenylenevinylene] and Polystyrene

Two series of binary blends of regioregular poly(3-hexylthiophene) (PHT) with a polymer semiconductor, poly[2-methoxy-5-(2-ethylhexoxy)-1,4-phenylenevinylene] (MEH−PPV), and with an insulating polymer, polystyrene, were investigated and found to be phase separated and to exhibit relatively high field-effect mobility of holes ((0.1−6) × 10-3 cm2/(V s)). Atomic force microscopy showed nucleation and growth type phase separation on the length scale of 100−600 nm in the binary blend systems. The mobility of holes in PHT/polystyrene blends is up to 7-fold higher than in PHT/MEH−PPV blends. The reduced carrier mobility in the PHT/MEH−PPV blends is due to dipolar effects arising from the polarity of the components. These results show for the first time that dipolar effects can substantially modify the charge transport properties of blends of conjugated polymers.

Thermomechanical and thermogravimetric analysis of blends of poly (vinyl chloride) (PVC) with maleic anhydride–allyl propionate copolymer

Binary blends of poly (vinyl chloride) (PVC) and the maleic anhydride–allyl propionate (MA–AP) copolymer have been prepared in tetrahydrofurane solution, aimed the improvement of the thermomechanical properties. The blends in the form of films were studied using thermomechanical analyzer (TMA). The glass transition temperatures ( T g), thermal expansion coefficient ( α) and other thermomechanical data for the blends were calculated. Consequently, according to increase in ratio of the MA–AP copolymer in the mixture, the MA–AP copolymer has a plasticing affect on the PVC.

Immiscible Poly(L‐lactide)/Poly(ε‐caprolactone) Blends: Influence of the Addition of a Poly(L‐lactide)‐Poly(oxyethylene) Block Copolymer on Thermal Behavior and Morphology

AbstractSummary: A binary blend of poly (L‐lactide) (PLLA) and poly(ε‐caprolactone) (PCL) of composition 70:30 by weight was prepared using a twin screw miniextruder and investigated by differential scanning calorimetry (DSC), optical microscopy and scanning electron microscopy (SEM). Ternary 70:30:2 blends were also obtained by adding either a diblock copolymer of PLLA and poly(oxyethylene) (PEO) or a triblock PLLA‐PCL‐PLLA copolymer as a third component. Optical microscopy revealed that the domain size of dispersed PCL domains is reduced by one order of magnitude in the presence of both copolymers. SEM confirmed the strong reduction in particle size upon the addition of the copolymers, with an indication of an enhanced emulsifying effect in the case of the PLLA‐PEO copolymer. These results are analyzed on the basis of solubility parameters of the blend components.Optical micrograph of M3EG2 blend melt quenched at 125 °C.imageOptical micrograph of M3EG2 blend melt quenched at 125 °C.

Thermomechanical and thermogravimetric analysis of blends of poly (vinyl chloride) (PVC) with maleic anhydride?allyl propionate copolymer

Binary blends of poly (vinyl chloride) (PVC) and the maleic anhydride–allyl propionate (MA–AP) copolymer have been prepared in tetrahydrofurane solution, aimed the improvement of the thermomechanical properties. The blends in the form of films were studied using thermomechanical analyzer (TMA). The glass transition temperatures (Tg), thermal expansion coefficient (α) and other thermomechanical data for the blends were calculated. Consequently, according to increase in ratio of the MA–AP copolymer in the mixture, the MA–AP copolymer has a plasticing affect on the PVC.

Spinodal Decomposition in Binary Blend of Poly(methyl methacrylate)/Poly(α-methyl styrene-co-acrylonitrile): Analysis of Early and Late Stage Demixing

Summary: The phase separation kinetics of a poly(methyl methacrylate), PMMA, and poly(α-methylstyrene-co-acrylonitrile), PαMSAN, blend exhibiting a LCST-type phase diagram have been investigated as functions of temperature and demixing time for the near critical composition (PαMSAN/PMMA = 25:75) using a time-resolved light scattering technique. We found that the scattering data in the early stage spinodal decomposition (SD) can be well described by the linearized Cahn–Hilliard theory. Spinodal temperature Ts ∼ 171 °C was determined from Dapp versus T and qequation/tex2gif-stack-1.gif versus T based on the analysis of Cahn theory in the early stage SD, where Dapp is the apparent diffusion coefficient and qm is the scattering vector at the maximum scattering intensity. The value of Ts obtained from the analysis of light scattering data was in good agreement with the phase diagram obtained visually at the equilibrium condition. The LCST-type phase diagram of this blend was also calculated using the Flory–Huggen theory. The estimated interaction parameter used for the calculation of the phase diagram was found to be composition and temperature dependent. The coarsening behavior of the blend at the late stage SD was also studied by analyzing the magnitudes of qm and Im at various demixing times and temperatures based on the nonlinear statistical theories. Both of qm and Im obtained at different times and temperatures can be superposed and reduced to the respective master curves by horizontal shifting when they are plotted against log (t/aT) at a given reference temperature, where aT is the temperature-dependent shift factor. The shape of the phase separation domain structures as a function of time during the SD was also considered. The scaling structure function F(x,t;T) = qm(t;T)3I(q,t;T) versus q/qm was found to be time independent and falls onto a universal curve in the late stage SD as a result of the dynamical self-similarity accompanying with the phase separation process. Optical microscopy pictures for the structure development of spinodal decomposition for PαMSAN/PMMA = 25:75 blend at 180 °C for different demixing times.

Miscibility in binary blends of poly(vinyl phenol) and poly(n-alkylene 2,6-naphthalates)

We have performed Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) studies on blends of poly(vinyl phenol) (PVPh) with poly(n-alkylene 2,6-naphthalates) containing alkylene units of different lengths. The results indicate that each poly(ethylene 2,6-naphthalate) (PEN) and poly(trimethylene 2,6-naphthalate) (PTN) blend with PVPh is immiscible or partially miscible, but blends of poly(butylene 2,6-naphthalate) (PBN) with PVPh are miscible over the whole range of compositions in the amorphous state. FTIR spectroscopic analysis confirmed that significant degree of intermolecular hydrogen bonding occurs between the PBN ester carbonyl groups and the PVPh hydroxyl groups. The large difference in the degree of mixing in these blend systems is described in terms of the effect that chain mobility has on the accessibility of the ester carbonyl functional groups toward the hydroxyl groups of PVPh, which in turn impacts the miscibility of these blends.

Hydrogen‐Bonding Interaction and Crystalline Morphology in the Binary Blends of Poly(ε‐caprolactone) and Polyphenol Catechin

AbstractThe specific intermolecular hydrogen‐bonding interaction between the ester carbonyl groups of poly(ε‐caprolactone) (PCL) and the phenolic hydroxyl groups of catechin has been studied by Fourier‐transform infrared spectroscopy (FT‐IR) and differential scanning calorimetry (DSC). According to quantitative curve‐fitting analysis of the FT‐IR spectra of PCL/catechin blends, it was found that the fraction of hydrogen‐bonded carbonyl groups of PCL increased with catechin content, while that of hydrogen‐bonded hydroxyl groups of catechin decreased. The calculated crystallinity of PCL in the binary blends, based on the curve‐fitting results, suggested that the crystallization of PCL was restrained in the blends with catechin. Only single glass transition temperature, Tg, was observed over the whole range of blend compositions, which was between those of the pure components. The melting point, Tm, depressed and Tg increased, indicating also the existence of strong intermolecular association. The blend composition dependence of Tg could be predicted very well by the Kwei equation with a positive ‘q’ value of 124. With the aid of small angle X‐ray scattering measurement, the segregation of catechin was investigated. It was found that the extent of extra‐lamellar segregation increased with catechin content. It was suggested that the crystal growth rate played the dominant role in the formation of morphology. With decreasing crystal growth rate of PCL component in the blends, enough time has been given to catechin molecules to diffuse into extra‐lamellar region. magnified image

Studies on Binary Blends of Poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) and Natural Polyphenol Catechin: Specific Interactions and Thermal Properties

AbstractThe existence of a specific intermolecular hydrogen‐bonding interaction between poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) [P(3HB‐co‐3HH)] and (+)‐catechin in their blends was demonstrated by Fourier‐transform infrared spectroscopy (FT‐IR). It was found that the experimentally estimated fraction of hydrogen‐bonded carbonyl groups was much lower than the theoretically predicted maximum fraction. Only one glass transition temperature (Tg) occurred in the blends with the compositions detected by differential scanning calorimetry (DSC), being further confirmed by the results of dynamic mechanical thermal analysis (DMTA). The decrease of the melting point (Tm) and the increase of the glass transition temperature of the blends observed by the DSC measurements also suggested the existence of a strong intermolecular interaction. It was interesting to note that, as a low‐molecular‐weight compound, catechin showed a glass transition, which arises from strong self‐association. As expected, the crystalline structure of P(3HB‐co‐3HH) in the blends showed no change, but the crystallinity of the copolymer component in the blends, calculated by wide‐angle X‐ray diffraction, decreased with the increase of catechin weight content. Investigated by tensile experiments, the maximum strength and modulus decreased sharply with the increase of catechin content; on the contrary, the elongation changed slowly.The FT‐IR spectra in the wave‐number 1 680–1 780 cm−1 region for blends of P(3HB‐co‐3HH)/catechin. A: HBH; B: HBHC10; C: HBHC20; D: HBHC30; E: HBHC40; F: HBHC50; and G: catechin.magnified imageThe FT‐IR spectra in the wave‐number 1 680–1 780 cm−1 region for blends of P(3HB‐co‐3HH)/catechin. A: HBH; B: HBHC10; C: HBHC20; D: HBHC30; E: HBHC40; F: HBHC50; and G: catechin.

Phase dispersion–crosslinking synergism in binary blends of poly(vinyl chloride) with low‐density polyethylene: Entrapping phenomenon in PVC/LDPE/DCP blend

AbstractThe co‐crosslinked products and the entrapping phenomenon that may exist in a poly(vinyl chloride)/low density polyethylene/dicumyl peroxide (PVC/LDPE/DCP) blend were investigated. The results of selective extraction show that unextracted PVC was due to not being co‐crosslinked with LDPE but being entrapped by the networks formed by the LDPE phase. SBR, as a solid‐phase dispersant, can promote the perfection of networks of the LDPE phase when it is added to the PVC/LDPE blends together with DCP, which leads to more PVC unextracted and improvement of the mechanical properties of PVC/LDPE blends. Meanwhile, the improvement of the tensile properties is dependent mainly on the properties of the LDPE networks. Finally, the mechanism of phase dispersion–crosslinking synergism is presented. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1296–1303, 2003

Improvement of the thermal and mechanical properties of poly (vinyl chloride) in presence of poly (ethylene succinate)

Binary blends of poly (vinyl chloride) (PVC) and poly (ethylene succinate) (PES) have been prepared by solution blending aimed at the improvement of thermal and mechanical properties. Thermal properties of the blends were studied using scanning calorimetry (DSC), thermogravimetry (TG) and potentiometric rate of dehydrochlorination. The increase of the PES content in the blend leads to thermal stability of the blend as shown from the thermogravimetry and the rate of dehydrochlorination results. All blends exhibited one major glass transition temperature ( T g) whose position on the temperature scale is lowered with increasing level of PES. Mechanical properties of various blends of the two polymers were also measured.

Crystallization Process in Binary Blends of Poly(ε-caprolactone)-block-Polybutadiene Copolymers

The crystallization process in binary blends of poly(e-caprolactone)-block-polybutadiene (PCL-b-PB) copolymers has been investigated by time-resolved small-angle X-Ray scattering with synchrotron radiation (SR-SAXS), where the crystallization of PCL blocks induces a morphological transition both in neat copolymers but the crystallization rate is extremely different between them. The microdomain structure in the melt and the final morphology after crystallization were also measured by conventional SAXS, and the melting behavior of crystallized samples was observed by differential scanning calorimetry (DSC). The binary blend forms a single microdomain structure in the melt over the whole composition range investigated, and the crystallization proceeds with an intermediate rate between those of the constituent PCL-b-PB copolymers to result in a single lamellar morphology. The time dependence of SR-SAXS curves is qualitatively similar in features to that for the crystallization of pure PCL-b-PB copolymers, suggesting that the crystallization of the blend is substantially controlled by a single crystallization mechanism. The remarkable change in the crystallization rate with composition is ascribed to the difference in the stability of preexisting microdomain structures. The conformation of (longer and shorter) PB blocks in the final lamellar morphology is qualitatively discussed.

Effect of End Groups on the Thermotropic Behavior of Linear Poly[11-(4‘-cyanophenyl-4‘ ‘-phenoxy)undecyl acrylate]s Prepared by ATRP and Their Topological Blends

Linear poly[11-(4‘-cyanophenyl-4‘ ‘-phenoxy)undecyl acrylate]s with 9−77 (GPC relative to linear polystyrene) or 7−101 (GPCLS) repeat units were synthesized by atom transfer radical polymerization of 11-(4‘-cyanophenyl-4‘ ‘-phenoxy)undecyl acrylate using a mesogenic initiator, 11-(4‘-cyanophenyl-4‘ ‘-phenoxy)undecyl 2-bromopropionate. The biphasic regions of the smectic A to isotropic (sA−i) transition of the linear polymers are extremely narrow, with full widths at half of the maximum peak intensity (fwhm) = 4.52−7.74 °C, in contrast to that of the corresponding polymer prepared by conventional radical polymerization (fwhm = 17.0 °C). The breadths of this transition do not vary with chain length, in contrast to the corresponding linear polymers with methyl propionate end groups. The breadth of the sA−i biphasic region of 1:1 binary blends of poly[11-(4‘-cyanophenyl-4‘ ‘-phenoxy)undecyl acrylate]s increases relatively linearly with the difference in end group (and therefore branching) density of the two components, regardless of the combination of molecular architectures (linear, three-arm star, or comb) or the type of end groups (bromine and hydrogen or methyl propionate).