Thermotropic liquid‐crystalline copolyester/thermoplastic elastomer in situ composites. I. Rheology,morphology, and mechanical properties of extruded strands

A thermotropic liquid‐crystalline polymer (TLCP), a copolyester with a 60/40 molar ratio of p‐hydroxy benzoic acid and poly(ethylene terephthalate), was blended with a styrene/ethylene butylene/styrene thermoplastic elastomer with a twin‐screw extruder. The rheological behavior, morphology, and mechanical properties of the extruded strands of the blends were investigated. The rheological measurements were performed on a capillary rheometer in the shear rate range of 5–2000 s^?1 and on a plate‐and‐plate rheometer in the frequency range of 0.6–200 rad s^?1. All the neat components and blends exhibited shear thinning behavior. Both the shear and complex viscosities of all the blends decreased with increasing TLCP contents, but the decrease in the shear viscosity was more pronounced. The best fibrillar morphology was observed in the extruded strands of a blend containing 30 wt % TLCP, and a lamellar structure started to form at 40 wt % TLCP. With an increasing concentration of TLCP, the tensile modulus of the blends was greatly enhanced, whereas the tensile strength was almost unchanged. The elongation at break of the blends first slightly decreased with the addition of TLCP and then sharply dropped at 40 wt % TLCP. The tension set measured at 200% deformation slightly increased with increasing TLCP contents up to 30 wt %, over which the set value was unacceptable for a thermoplastic elastomer. A remarkable improvement in the dynamic mechanical properties of the extruded strands was observed in the blends with increasing amounts of TLCP. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2676–2685, 2003     

Self‐reinforcing elastomer composites based on polyolefinic thermoplastic elastomer and thermotropic liquid crystalline polymer

In situ reinforcing elastomer composites based on Santoprene thermoplastic elastomer, a polymerized polyolefin compound of ethylene–propylene–diene monomer/polypropylene, and a thermotropic liquid crystalline polymer (TLCP), Rodrun LC3000, were prepared using a single‐screw extruder. The rheological behavior, morphology, mechanical, and thermal properties of the blends containing various LC3000 contents were investigated. All neat components and their blends exhibited shear thinning behavior. With increasing TLCP content, processability became easier because of the decrease in melt viscosity of the blends. Despite the viscosity ratio of dispersed phase to the matrix phase for the blend system is lower than 0.14, most of TLCP domains in the blends containing 5–10 wt % LC3000 appeared as droplets. At 20 wt % LC3000 or more, the domain size of TLCP became larger because of the coalescence of liquid TLCP threads that occurred during extrusion. The addition of LC3000 into the elastomer matrix enhanced the initial tensile modulus considerably whereas the extensibility of the blends remarkably decreased with addition of high TLCP level (>.20 wt %). The incorporation of LC3000 into Santoprene slightly improved the thermal resistance both in nitrogen and in air. Dynamic mechanical analysis results clearly showed an enhancement in dynamic moduli for the blends with 20–30 wt % LC3000. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Thermotropic liquid crystalline polymer (Rodrun LC5000)/polypropylene in situ composite films: rheology, morphology, molecular orientation and tensile properties

In situ composite films were prepared by a two-step method. First, polypropylene and thermotropic liquid crystalline polymer (TLCP), Rodrun LC5000 (80 mol% p-hydroxy benzoic acid (HBA)/20 mol% polyethylene terephthalate (PET)), were melt blended in a twin-screw extruder and then fabricated by extrusion through a mini-extruder as cast film. Rheological behavior of the blends, morphology of the extruded strands and films, and tensile properties of the in situ composite films were investigated. Rheological behavior of the blends at 295 °C studied using a plate-and-plate rheometer revealed a substantial reduction of the complex viscosity with increasing TLCP content, and all specimens exhibited shear thinning behavior. Over the angular frequency range of 0.6-200 rad/s, the viscosity ratio (dispersed phase to matrix phase) was found to be very low, in the range of 0.03-0.07. Morphologies of the fracture surfaces of the blend extrudates and the film surfaces etched in permanganic solution were investigated by scanning electron microscope (SEM). The TLCP droplets in the extruded strands were seen with a progressive deformation into fibrillar structure when TLCP content was increased up to 30 wt%. In the extruded films, TLCP fibrils with increasing aspect ratio (length to width) were observed with increasing TLCP concentration. Orientation functions of each component were determined by X-ray diffraction using a novel separation technique. It was observed that the Young's modulus in machine direction of the extruded film was greatly improved with increasing TLCP loading, due to the increase in fiber aspect ratio and also molecular orientation.     

Phase behavior and properties of in situ‐reinforcing elastomer composites based on thermoplastic elastomers and thermotropic liquid crystalline copolyester

In situ reinforcing composites based on two elastomer matrices very different in melt viscosity, styrene–(ethylene butylene)–styrene triblock copolymer (Kraton G1650) and styrene–(ethylene propylene) diblock copolymer (Kraton G1701), and a thermotropic liquid crystalline polymer (TLCP), Rodrun LC3000, were prepared using a twin‐screw extruder. The rheological behavior, morphology, mechanical and thermal properties of the blends containing various LC3000 contents were investigated. G1650 was found to have much higher shear viscosity than G1701. All neat components and their blends exhibited shear thinning behavior. Melt viscosity of the blends gradually decreased with increasing LC3000 contents. Despite a large difference in melt viscosity of the two matrices, the results showed that the fibrillar morphology was obtained for both as‐extruded strands of LC3000/G1650 and LC3000/G1701 with up to 30 wt % LC3000. At 40 wt % LC3000 or more, the lamellar structure was observed for both types of blends because of the coalescence of liquid TLCP threads that occurred during extrusion. The addition of LC3000 into both elastomer matrices enhanced the tensile modulus considerably whereas the extensibility remarkably decreased. The results obtained from thermogravimetric analysis suggested that an addition of LC3000 into both elastomer matrices improved the thermal resistance significantly in air, but not in nitrogen. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1610–1619, 2006     

The viscosity reducing effects of very low concentrations of a thermotropic copolyester in a matrix of HDPE

A thermotropic liquid crystalline polymer (TLCP), denoted as TLCP(1), was used as a processing aid for high density polyethylene (HDPE). The TLCP was a copolyester of hydroxybenzoic acid, hydroquinone and sebacic acid and was blended with HDPE to give 0.2, 0.5 and 2 wt% TLCP(1) blends. At a temperature of 185°C, when TLCP(1) is in the nematic regime, the processing window for HDPE was increased tenfold from a maximum shear rate of 100 s^?1 for pure HDPE to 1170 s^?1 for a 2 wt% TLCP(1) blend. There were large viscosity reductions of between 85% and 90% compared with the pure HDPE when the blended material was used at a wall shear stress value of approximately 2.4 × 10⁵ Pa. This viscosity reduction was attributed to the TLCP(1) droplets changing shape from spheres to slender fibrils under shear flows.     

Thermal,mechanical, and rheological properties of polylactide/poly(1,2‐propylene glycol adipate)

Polylactide (PLA) was melt blended with poly(1,2‐propylene glycol adipate) (PPA) in a Thermo‐Haake mixer. Thermal, mechanical, and rheological properties of the blends were investigated by means of differential scanning calorimetry, dynamic mechanical analysis, tensile test, and small amplitude oscillatory shear rheometry. PPA lowered the glass transition temperature and increased the ability of PLA to cold crystallization. With the increase in PPA content (5–25 wt%), the blends showed decreased tensile strength and Young's modulus; however, impact strength and elongation‐at‐break along were dramatically increased due to the plastic deformation. Morphological results of PLA/PPA blends showed that PPA was good compatible with PLA. The plasticization effect of PPA was also manifested by the lowering of dynamic storage modulus and viscosity in the melt state of the blends compared with neat PLA. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Compatibilizers for thermotropic liquid crystalline polymer/polyethylene blends prepared by reactive mixing

This paper describes the effects of composition and processing conditions on the efficiency of the compatibilizer prepared from a thermotropic liquid crystalline polymer (TLCP) and the sodium salt of a poly(ethylene‐co‐r‐acrylic acid) ionomer (EAA‐Na) in TLCP/low‐density polyethylene (LDPE) blends and TLCP/high‐density polyethylene (HDPE) blends. The TLCP‐ionomer graft copolymer formed by a melt acidolysis reaction effectively reduced the interfacial tension between TLCP and polyethylene, which improved impact strength and toughness of the compatibilized blends. Higher processing temperatures for the reactive extrusion produced a more efficient compatibilizer, presumably due to increased graft‐copolymer formation, but the reaction temperature had little effect on the impact strength of compatibilized blends for temperatures above 300°C. The addition of the compatibilizer to TLCP/LDPE blends significantly increased the melt viscosity due to increased interfacial adhesion. The TLCP/EAA‐Na ratio used to prepare the compatibilizer had little effect on the performance of the compatibilizer. Although the compatibilizer can be prepared in situ by blending and extruding a ternary blend of TLCP/EAA‐Na/polyethylene, pre‐reacting the compatibilizer resulted in blends with improved toughness and elongation.     

Dynamic rheological properties of high‐density polyethylene/polystyrene blends extruded in the presence of ultrasonic oscillations

The linear rheological properties of high‐density polyethylene (HDPE), polystyrene (PS), and HDPE/PS (80/20) blends were used to characterize their structural development during extrusion in the presence of ultrasonic oscillations. The master curves of the storage shear modulus (G′) and loss shear modulus (G″) at 200°C for HDPE, PS, and HDPE/PS (80/20) blends were constructed with time–temperature superposition, and their zero shear viscosity was determined from Cole–Cole plots of the out‐of‐phase viscous component of the dynamic complex viscosity (η″) versus the dynamic shear viscosity. The experimental results showed that ultrasonic oscillations during extrusion reduced G′ and G″ as well as the zero shear viscosity of HDPE and PS because of their mechanochemical degradation in the presence of ultrasonic oscillations; this was confirmed by molecular weight measurements. Ultrasonic oscillations increased the slopes of log G′ versus log G″ for HDPE and PS in the low‐frequency terminal zone because of the increase in their molecular weight distributions. The slopes of log G′ versus log G″ for HDPE/PS (80/20) blends and an emulsion model were used to characterize the ultrasonic enhancement of the compatibility of the blends. The results showed that ultrasonic oscillations could reduce the interfacial tension and enhance the compatibility of the blends, and this was consistent with our previous work. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3153–3158, 2004     

A comparative study of thermotropic LCP and organoclay as fillers in high molecular mass polyethylene with different blending sequences

The influences of thermotropic liquid crystalline copolyester (TLCP) on viscosity reduction in high molecular mass polyethylene (HMMPE) filled with organoclay were investigated by controlling the blending sequence. The interactions between organoclay and TLCP in HMMPE create different morphologies and influence rheological properties of the clay/TLCP/HMMPE blends. When the organoclay was blended with TLCP first, large amounts of organoclay formed partially intercalated structures in TLCP, with phase separation occurring at the temperature when TLCP was in the nematic phase, corresponding an antagonistic effect which weakens viscosity reduction ability of TLCP for HMMPE. However, with first blending of TLCP with HMMPE and then adding organoclay into the blend, most of the organoclay enriched on TLCP surfaces in the blend. Such interaction prevents TLCP droplets from coalescing at high shear stresses, enlarging the processing window. A phenomenological model, originally for HMMPE/TLCP systems, was successfully adopted to predict the flow behaviors of clay/HMMPE/TLCP blends. POLYM. ENG. SCI., 50:1679–1688, 2010. © 2010 Society of Plastics Engineers     

Effect of cellulose nanofibers and acetylated cellulose nanofibers on the properties of low‐density polyethylene/thermoplastic starch blends

The aim of this study was to evaluate the effect of cellulose nanofibers (CNFs) and acetylated cellulose nanofibers (ACNFs) on the properties of low‐density polyethylene/thermoplastic starch/polyethylene‐grafted maleic anhydride (LDPE/TPS/PE‐g‐MA) blends. For this purpose, CNFs, isolated from wheat straw fibers, were first acetylated using acetic anhydride in order to modify their hydrophilicity. Afterwards, LDPE/TPS/PE‐g‐MA blends were reinforced using either CNFs or ACNFs at various concentrations (1–5 wt%) with a twin‐screw extruder. The mechanical results demonstrated that addition of ACNFs more significantly improved the ultimate tensile strength and Young's modulus of blends than addition of CNFs, albeit elongation at break of both reinforced blends decreased compared with the neat sample. Additionally, biodegradability and water absorption capacity of blends improved due to the incorporation of both nanofibers, these effects being more pronounced for CNF‐assisted blends than ACNF‐reinforced counterparts. © 2018 Society of Chemical Industry     

Compatibilizing effect of ethylene–propylene–diene grafted maleic anhydride terpolymer on the blend of polyamide 66 and thermal liquid crystalline polymer

Polyamide 66–thermal liquid crystalline polymer (PA66/TLCP) composites containing 10 wt% TLCP was compatibilized by ethylene–propylene–diene‐grafted maleic anhydride terpolymer (MAH‐g‐EPDM). The blending was performed on a twin‐screw extrusion, followed by an injection molding. The rheological, dynamic mechanical analysis (DMA), thermal, mechanical properties, as well as the morphology and FTIR spectra, of the blends were investigated and discussed. Rheological, DMA, and FTIR spectra results showed that MAH‐g‐EPDM is an effective compatibilizer for PA66/TLCP blends. The mechanical test indicated that the tensile strength, tensile elongation, and the bending strength of the blends were improved with the increase of the content of MAH‐g‐EPDM, which implied that the blends probably have a great frictional shear force, resulting from strong adhesion at the interface between the matrix and the dispersion phase; while the bending modulus was weakened with the increase of MAH‐g‐EPDM content, which is attributed to the development of the crystalline phase of PA66 hampered by adding MAH‐g‐EPDM. POLYM. COMPOS., 27:608–613, 2006. © 2006 Society of Plastics Engineers     

The effect of TLCP melt structure on the bulk viscosity of high molecular mass polyethylene

A thermotropic liquid crystalline polyester (TLCP), denoted as TCLP3 and based on hydroxybenzoic acid, hydroquinone and sebacic acid, was used as a processing aid in the extrusion of high molecular mass polyethylene (HMMPE). This TLCP is in the nematic phase at 179.6–182°C. Capillary rheometry experiments were carried out at two processing temperatures: 190°C and 230°C. At 190°C TLCP3 is predominantly nematic and at 230°C it is predominantly isotropic. It is an effective processing aid for HMMPE, particularly at 190°C, with viscosity reductions in excess of 90% with a 1 wt% TLCP3/HMMPE blend. The rheological characteristics of the blends have been linked to the optical textures of the TLCP3 using hot-stage optical microscopy. From the experimental observations speculations are made about the mechanisms of viscosity reduction. Initial viscosity reductions are caused by TLCP3 structure effects (fibrillation and phase change), giving rise to fibrillation-induced molecular orientation in the neighboring HMMPE phase. This is only effective when nematic structures are present. Above a critical wall shear stress value the lubrication effect due to TLCP3 migration is dominant.     

Effects of process conditions on Young's modulus and strength of extrudate in short‐fiber‐reinforced polypropylene

We examined the effects of process conditions on Young's modulus and tensile strength of extruded short‐fiber reinforced thermoplastics. With increasing extrusion ratio and decreasing extrusion temperature, the fiber alignment increases, the mean fiber length decreases, and the mechanical properties of the matrix are improved. The orientation parameter, mean fiber length, Young's modulus, and tensile strength of the matrix are described as a function of extrusion ratio and extrusion temperature. The models proposed by Fukuda and Kawata, and Fukuda and Chou are applied to predict Young's modulus and tensile strength of the composites using orientation parameter. By comparing the predicted Young's modulus and tensile strength with experimental results, the validity of the models is examined. The prediction of Young's modulus agreed quit with the experimental results. The tensile strength of composite extruded below the melting point nearly matched that of the neat matrix. There is no the strengthening effect of the fiber since the angle between fracture surface and fiber direction is very small. POLYM. COMPOS. 28:29–35, 2007. © 2007 Society of Plastics Engineers     

Fibrillation of thermotropic liquid crystalline polymer enhanced by nano-clay in nylon-6 matrix

The influence of well-dispersed nano-clay filler on the morphology of thermotropic liquid crystalline polymer (TLCP) in nylon-6 matrix was investigated by melt extrusion process. The good dispersion of clay in the hybrid blends was confirmed by X-ray diffraction, transmission electron microscopy and rheological measurement. Morphological observation showed that the clay platelets had dramatic influences on the dispersion and deformation of TLCP phase. The TLCP droplets got smaller at the clay content ≤3 wt%, and deformed into fibrils at the clay content up to 5 and 7 wt%. The morphology evolution of TLCP in the hybrid blends, especially at 7 wt% of clay loading, was consistent well with the prediction based on the micro-rheology parameters such as the viscosity ratio of the dispersed phase to the matrix (η_d/η_m) and the ratio of capillary number to the critical capillary number (Ca/Ca_crit). This enhanced fibrillation of TLCP droplets was attributed to the role of nano-clay particles as a compatibilizer to improve the interfacial adhesion and to suppress the interfacial slip between TLCP and nylon phases in the melt, so that the shear stress was effectively transferred to the dispersed TLCP phase.     

Blends of polylactic acid with thermoplastic copolyester elastomer: Effect of functionalized terpolymer type on reactive toughening

This study is an attempt to explore the effectiveness of thermoplastic copolyester elastomer (TPCE) as a toughening agent for improving the impact strength of PLA. Biobased Hytrel^® thermoplastic copolyester of polyether glycol and polybutylene terephthalate was selected as the TPCE of choice for this study. Blends of PLA/Hytrel at varying weight ratios were prepared using extrusion followed by injection molding technique. Optimal synergies of two polymers were found in the PLA/Hytrel (70/30) blend, showing impact strength of 234 J/m, a sixfold increase compared to neat PLA. In order to obtain further enhancement in toughness, different functionalized terpolymers were added to accomplish reactive compatibilization. A series of functionalized terpolymers, ethylene methyle acrylate‐glycidyl methacrylate (EMA‐GMA), ethylene butyl acrylate‐glycidyl methacrylate (EBA‐GMA), ethylene methyl acrylate‐maleic anhydride (EMA‐MaH), and ethylene butyl acrylate‐maleic anhydride (EBA‐MaH) were selected. Comparing PLA ternary blends with different terpolymers, GMA containing terpolymers showed better impact toughness compared to MaH terpolymer blends. Unique fracture surface morphology showing debonding cavitation and massive shear yielding in the ternary blends containing EMA‐GMA resulted in super toughened blends. Highest zero shear viscosity and storage modulus was also observed for ternary blends with EMA‐GMA. Under the processing conditions and blend ratio investigated, EMA‐GMA showed better efficiency in improving the toughness of the PLA blends. POLYM. ENG. SCI., 58:280–290, 2018. © 2017 Society of Plastics Engineers     

Preparation and characterization of high melt strength polypropylene with long chain branched structure by the reactive extrusion process

The reactive extrusion of maleic anhydride grafted polypropylene (PP‐g‐MAH) with ethylenediamine (EDA) as coupling agent is carried out in a corotating twin‐screw extruder to produce long chain branched polypropylene (LCBPP). Part of PP‐g‐MAH is replaced by maleic anhydride grafted high‐density polyethylene (HDPE‐g‐MAH) or linear low‐density polyethylene (LLDPE‐g‐MAH) to obtain hybrid long chain branched (LCB) polyolefins. Compared with the PP‐g‐MAH, PE‐g‐MAH, and their blends, the LCB polyolefins exhibit excellent dynamic shear and transient extensional rheological characteristics such as increased dynamic modulus, higher low‐frequency complex viscosity, broader relaxation spectra, significantly enhanced melt strength and strain‐hardening behaviors. The LCB polyolefins also have higher tensile strength, tensile modulus, impact strength and lower elongation at break than their blends. Furthermore, supercritical carbon dioxide (scCO₂) is constructively introduced in the reactive extrusion process. In the presence of scCO₂, the motor current of the twin extruder is decreased and LCB polyolefins with lower melt flow rate (MFR), higher complex viscosity and increased tensile strength and modulus can be obtained. This indicates that the application of scCO₂ can reduce the viscosity of melt in extruder, enhance the diffusion of reactive species, and then facilitate the long chain branching reaction between anhydride group and primary amine group. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effects of ultrasonic oscillations on processing behavior and mechanical properties of metallocene‐catalyzed linear low‐density polyethylene/low‐density polyethylene blends

The influences of ultrasonic oscillations on rheological behavior and mechanical properties of metallocene‐catalyzed linear low‐density polyethylene (mLLDPE)/low‐density polyethylene (LDPE) blends were investigated. The experimental results showed that the presence of ultrasonic oscillations can increase the extrusion productivity of mLLDPE/LDPE blends and decrease their die pressure and melt viscosity during extrusion. Incorporation of LDPE increases the critical shear rate for sharkskin formation of extrudate, crystallinity, and mechanical properties of mLLDPE. The processing behavior and mechanical properties of mLLDPE/LDPE blends were further improved in the presence of ultrasonic oscillations during extrusion. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2522–2527, 2004     

Preparation and studying properties of polybutene‐1/thermoplastic starch blends

Starch as an inexpensive and renewable source has been used as a filler for environmental friendly plastics for about two decades. In this study, glycerol was used as a plasticizer for starch to enhance the dispersion and the interfacial affinity in thermoplastic starch (TPS)/polybutene‐1(PB‐1) blend. PB‐1 was melt blended with TPS using a single screw extrusion process and molded using injection molding process to investigate the rheological and mechanical properties of these blends. Rheological properties were studied using a capillary rheometer, and the Bagley's correction was performed. Mechanical analysis (stress–strain curves) was performed using Testometric M350‐10 kN. The rheological properties showed that the melt viscosity of the blend is less than that of PB‐1, and the flow activation energy at a constant shear stress of the blend increases with increasing glycerol content in the blend. The mechanical experiments showed that both stress and strain at break of the blends are less than that of PB‐1, whereas the Young's modulus of the most blends is higher than that of PB‐1 which confirms the filling role of TPS in the blend. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Preparation of poly(vinyl alcohol) films with promising physical properties in comparison with commercial polyethylene film

Poly(vinyl alcohol) (PVA) films with different thicknesses (0.08, 0.2, 0.23, 0.42 mm) were prepared by a casting technique. The transmission and the absorption of the PVA films were measured as functions of the wavelengths. PVA film with a thickness of 0.42 mm showed zero transmission in the wavelength range of 190–350 nm. The transmission spectrum of a commercial polyethylene film with a thickness of 0.21 mm was compared to the transmission spectrum of PVA film with a thickness of 0.42 mm. A correlation was found between the two transmission spectra in the region 190–350 nm and a 20% increase in the transmission of the PVA film in comparison with the transmission of commercial polyethylene in the region 350–1500 nm. The near‐infrared region of the transmission of commercial polyethylene was increased by 15% with respect to the transmission of the PVA film. The stress–strain measurements were done for PVA and commercial polyethylene films. The Young's modulus and the strength at break for PVA films are higher by two orders of magnitude than those for commercial polyethylene film. The strain at break for commercial polyethylene is 17% lower than that for PVA film. Radiation effects on the optical properties of PVA and commercial polyethylene films were investigated. The PVA and commercial polyethylene films were irradiated with a xeon arc lamp at 3.5–5 W/cm². The optical properties for PVA and commercial polyethylene films were studied after irradiation. The obtained results showed that PVA film with a thickness of 0.42 mm gave promising properties which could be used in technological applications. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1219–1226, 2002     

Well-mixed blends of HDPE and ultrahigh molecular weight polyethylene with major improvements in impact strength achieved via solid-state shear pulverization

Compared with conventional polyolefins, ultrahigh molecular weight polyethylene (UHMWPE) possesses outstanding impact strength and crack resistance that make it desirable for a wide variety of applications. Unfortunately, UHMWPE has an ultrahigh viscosity that renders common, continuous melt-state processes ineffective for making UHMWPE products. Attempts to overcome this problem by blending UHMWPE with lower molecular weight high-density polyethylene (HDPE) by melt processing have typically led to poorly dispersed blends due to the vast viscosity mismatch between blend components. Here, we present solid-state shear pulverization (SSSP) as a mild, continuous, and simple approach for achieving effective and intimate mixing in UHMWPE/HDPE blends. These SSSP blends are easily processed by post-SSSP melt extrusion; for an SSSP blend with 50 wt% UHMWPE, we observe more than a factor of 1000 increase in viscosity at a shear rate of 0.01 s⁻¹ but less than a factor of 5 increase at 100 s⁻¹, the latter being more typical of melt-processing operations. Using extensional rheology, we confirm the strain hardening behavior of SSSP blends. Shear rheology and crystallization data show that the mixing between UHMWPE and HDPE can be improved with subsequent passes of SSSP and single-screw extrusion. Finally, we show that blending via SSSP leads to dramatic improvements in impact strength: as compared to literature results, injection-molded sample bars made from SSSP blends with 30–50 wt% UHMWPE exhibit very high values of notched Izod impact strength, 660–770 J/m (the impact strength of neat HDPE was 170 J/m).