Development of phase morphology in immiscible poly(styrene‐co‐acrylonitrile)/poly(butylene terephthalate) nanoblends: Mechanical properties and effect of the compatibilizer

Nanoblends were obtained from poly(styrene‐co‐acrylonitrile) (SAN) as a matrix, and poly(butylene terephthalate) (PBT) was used as a nanodispersed phase. Compatibilized SAN/PBT blends were prepared by reactive extrusion, and the PBT concentrations ranged between 3 and 30 wt %. Nanoblends were obtained for up to 10 wt % PBT concentrations in the presence of the compatibilizer. With 20 and 30 wt % PBT, the extruded material presented a droplet dispersed phase. The same blends were subjected to an injection‐molding process, which provided a cocontinuous phase morphology. The influence of the concentration of the dispersed phase and the type of morphology on the mechanical behavior of tensile test, flexural test, impact test, and deflection temperature of the blends was analyzed. The results show an important reduction in the particle size of the dispersed phase, which was due to the presence of the compatibilizer. Furthermore, the type of morphology and an excess of compatibilizer exerted a stronger influence on the mechanical properties than the particle size of the dispersed phase. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45030.     

Effects of the molecular structure of impact modifier and compatibilizer on the toughening of PBT/SBS/PS‐GMA blends

This work aims at studying the toughening process of poly(butylene terephthalate) (PBT) through its blends with styrene‐butadiene‐styrene block copolymers (SBS), in the presence of poly(styrene‐ran‐glicydil methacrylate) (PS‐GMA) as reactive compatibilizer. High values of impact strength were attained for PBT/SBS blends without the compatibilizer; however, this improvement is achieved for blends with SBS having similar viscosity compared to PBT, at high SBS content (40 wt %) and for blends prepared under specific processing conditions. The efficiency of the in situ compatibilization of PBT/SBS blends by PS‐GMA was found to be strongly dependent on the SBS and PS‐GMA molecular characteristics. Better compatibilizing results were observed through fine phase morphologies and lower ductile to brittle transition temperatures (DBTT) as the interfacial interaction and stability of the in situ formed compatibilizer are maximized, that is, when the miscibility between SBS and PS‐GMA and reaction degree between PBT and PS‐GMA are maximized. For the PBT/SBS/PS‐GMA blends under study, this was found when it is used the SBS with higher polystyrene content (38 wt %) and with longer PS blocks (M_w = 20,000 g mol^?1) and also the PS‐GMA with moderate GMA contents (4 wt %) and with molecular weight similar to the critical one for PS entanglements (M_c = 35,000 g mol^?1). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5795–5807, 2006     

Mechanical properties and morphology of polylactide,linear low‐density polyethylene,and their blends

Melt blending of linear low density polyethylene (LLDPE) and polylactide (PLA) was performed in an extrusion mixer with post extrusion blown film attachment with and without compatibilizer‐grafted low density polyethylene maleic anhydride. The blend compositions were optimized for tensile properties as per ASTM D 882‐91. On the basis of this, LLDPE 80 [80 wt % LLDPE and 20 wt % poly(L ‐lactic acid) (PLLA)] and MA‐g‐low‐density polyethylene 80/4 (80 wt % LLDPE, 20 wt % PLLA, and 4 phr compatibilizer) were found to be an optimum composition. The blends were characterized according to their mechanical, thermal, and morphological behavior. Fourier transform infrared spectroscopy revealed that the presence of compatibilizer enhanced the blend compatibility to some extent. The morphological characteristics of the blends with and without compatibilizer were examined by scanning electron microscopy. The dispersion of PLLA in the LLDPE matrix increased with the addition of compatibilizer. This blend may be used for packaging applications. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Morphological and mechanical properties of PP/ABS blends compatibilized with PP‐g‐acrylic acid

Polypropylene (PP) and acrylonitrile–butadiene–styrene (ABS) blends were prepared by a melt extrusion process. PP‐g‐acrylic acid was used as a compatibilizer. Blends with various compositions of PP, compatibilizer, and ABS were prepared and studied for morphological and mechanical properties. PP‐rich ternary blends showed good morphological and mechanical properties. The use of 5 wt % PP‐g‐acrylic acid as a compatibilizer resulted in a fine and homogeneous dispersion of the ABS phase in the PP phase. The experimental data of the tensile modulus showed good agreement in PP‐rich compositions with that generated from Kerner's model with perfect adhesion. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1731–1741, 2001     

Effect of interface affinity on the performance of a composite of microcrystalline cellulose and polypropylene/polylactide blends

The effects of compatibilizer and fillers on the mechanical properties and dispersion state of droplets of polypropylene (PP)/polylactide (PLA) blends were investigated. Two blended composite systems, i.e. PP‐rich (80/20) containing microcrystalline cellulose (MCC) modified with silane (m‐MCC) and PLA‐rich (20/80) containing MCC were prepared by melt compounding using a twin‐screw extruder. The structural differences between MCC and m‐MCC were confirmed using Fourier transform infrared spectra. Universal testing machine results revealed that the tensile strength and Young's modulus increased with the addition of compatibilizer and filler, respectively. These results were supported by the reduction of domain size observed by scanning electron microscopy. Differential scanning calorimetric analysis showed a change of the melting and crystallization behavior of blends according to the presence of compatibilizer or filler. An increase of the dynamic storage modulus and a decrease in tan δ with addition of compatibilizer indicated that the interfacial adhesion between PP and PLA improved. © 2019 Society of Chemical Industry     

Properties of uncompatibilized and compatibilized poly(butylene terephthalate)–LLDPE blends

In this work, blends of poly(butylene terephthalate) (PBT) and linear low‐density polyethylene (LLDPE) were prepared. LLDPE was used as an impact modifier. Since the system was found to be incompatible, compatibilization was sought for by the addition of the following two types of functionalized polyethylene: ethylene vinylacetate copolymer (EVA) and maleic anhydride‐grafted EVA copolymer (EVA‐g‐MAH). The effects of the compatibilizers on the rheological and mechanical properties of the blends have been also quantitatively investigated. The impact strength of the PBT–LLDPE binary blends slightly increased at a lower concentration of LLDPE but increased remarkably above a concentration of 60 wt % of LLDPE. The morphology of the blends showed that the LLDPE particles had dispersed in the PBT matrix below 40 wt % of LLDPE, while, at 60 wt % of LLDPE, a co‐continuous morphology was obtained, which could explain the increase of the impact strength of the blend. Generally, the mechanical strength was decreased by adding LLDPE to PBT. Addition of EVA or EVA‐g‐MAH as a compatibilizer to PBT–LLDPE (70/30) blend considerably improved the impact strength of the blend without significantly sacrificing the tensile and the flexural strength. More improvement in those mechanical properties was observed in the case of the EVA‐g‐MAH system than for the EVA system. A larger viscosity increase was also observed in the case of the EVA‐g‐MAH than EVA. This may be due to interaction of the EVA‐g‐MAH with PBT. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 989–997, 1999     

Use of Functionalized Metallocene Copolymers from Ethylene and Polar Olefins as Compatibilizers for Low‐Density‐Polyethylene/Starch and Low‐Density‐Polyethylene/Dextran Blends

Summary: Functionalized metallocene copolymers synthesized from ethylene with 5‐hexen‐1‐ol and ethylene with 10‐undecen‐1‐ol were used as compatibilizers in LDPE/starch and LDPE/dextran blends in order to improve the interfacial adhesion between hydrophobic LDPE and hydrophilic natural polymers. An increase in tensile modulus and a slight decrease in tensile strength was observed when poly[ethylene‐co‐(10‐undecen‐1‐ol)] was added to a 70:30 wt.‐% LDPE/dextran blend, whereas the addition of poly[ethylene‐co‐(5‐hexen‐1‐ol)] as compatibilizer resulted in obtaining a more rigid material with a slightly higher modulus. Scanning electron microscopy of modified dextran blends containing 3 wt.‐% of both compatibilizers showed some degree of phase cocontinuity. Enhanced interfacial adhesion and decrease in particle size of starch was observed when 5 wt.‐% of poly [ethylene‐co‐(5‐hexen‐1‐ol)] copolymer was used as the compatibilizer in starch blends. The crystallization temperature of LDPE, determined by DSC, was shifted to a slightly higher temperature as a consequence of the addition of the compatibilizers. The existence of phase segregation was also revealed by thermal analysis when 5 wt.‐% of the copolymers were used as blend modifiers.

SEM micrograph of 70:30 wt.‐% LDPE/dextran blend with added poly[ethylene‐co‐(5‐hexen‐1‐ol)] compatibilizer.     

Use of epoxy reactivity for compatibilization of PP/PBT and PP/LCP blends

Binary blends of a reactive ethylene-based terpolymer with polybutylene terephthalate (PBT) and with a liquid crystalline polyester (LCP) were studied to clarify the possible interactions between the blended polymers. The aim was to determine the suitability of the reactive terpolymer containing epoxy reactivity as a compatibilizer in blends of polypropylene (PP) and these two polyesters. The binary blends exhibited increased viscosity during blending, changes in the crystallization of the PBT phase, and an intimate contact between the blended polymers, which pointed to strong interactions or chemical reactions between the compatibilizer and both PBT and LCP. FTIR analysis confirmed the reaction of the epoxide and formation of new esters. Most probably the carboxyl end groups of the polyesters reacted with the epoxy group of the compatibilizer. In the second part of the work the same terpolymer was shown to act as a compatibilizer in PP/PBT and PP/LCP blends. This behavior was based on good mixing with the PP phase and on the chemical reactivity or strong interactions with the polyesters demonstrated in the investigations on binary blends. Addition of 5 wt% of the compatibilizer improved the impact strength, especially in PP/PBT blends where synergistic behavior was found at compositions of 80/20 and 20/80. In PP/LCP blends, the compatibilizer significantly improved the impact strength of unnotched samples at 20 wt % LCP content. In both blends, the compatibilizer reduced the size of the dispersed domains and caused them to attach better in the matrix. © 1995 John Wiley & Sons, Inc.     

Synthesis and properties of reactively compatibilized polyester and polyamide blends

The functionalization of poly(butylene terephthalate) (PBT) has been accomplished in a twin screw extruder by grafting maleic anhydride (MA) using a free radical polymerization technique. The resulting PBT‐g‐MA was successfully used as a compatibilizer for the binary blends of polyester (PBT) and polyamide (PA66). Enhanced mechanical properties were achieved for the blend containing a small amount (as low as 2.5 %) of PBT‐g‐MA compared to the binary blend of unmodified PBT with PA66. Loss and storage moduli for blends containing compatibilizer were higher than those of uncompatibilized blends or their respective polymers. The grafting and compatibilization reactions were confirmed using FTIR and ¹³C NMR spectroscopy. The properties of these blends were studied in detail by varying the amount of compatibilizer, and the improved mechanical behaviour was correlated with the morphology with the help of scanning electron microscopy. Morphology studies also revealed the interfacial interaction in the blend containing grafted PBT. The improvement in the properties of these blends can be attributed to the effective interaction of grafted maleic anhydride groups with the amino group in PA66. The results indicate that PBT‐g‐MA acts as an effective compatibilizer for the immiscible blends of PBT and PA66. © 2000 Society of Chemical Industry     

From microstructure to mechanical properties of compatibilized polylactide/thermoplastic starch blends

Bio‐degradable polymer blends of polylactic acid/thermoplastic starch (PLA/TPS) were prepared via direct melt blending varying order of mixing of ingredients fed into the extruder. The effect of interface interactions between PLA and TPS in the presence of maleic anhydride (MA) compatibilizer on the microstructure and mechanical properties was then investigated. The prepared PLA/TPS blends were characterized by scanning electron microscopy, differential scanning calorimetry (DSC), tensile, and rheological measurements. Morphology of PLA/TPS shows that the introduction of MA into the polymer matrix increases the presence of TPS at the interface region. DSC results revealed the reduction of glass transition temperature of PLA with contributions from both TPS and MA. The crystallization temperature was decreased by the addition of MA leading to reduction of overall crystallization of PLA/TPS blend. The mechanical measurements show that increasing MA content up to 2 wt % enhances the modulus of PLA/TPS more than 45% compared to the corresponding blends free of MA compatibilizer. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44734.     

An investigation on recycled PET/PP and recycled PET/PP‐EP compatibilized blends: Rheological,morphological, and mechanical properties

The effectiveness of P(E‐co‐MA‐co‐GMA) as a compatibilizer for recycled PET/PP and recycled PET/PP‐EP (polypropylene (ethylene‐propylene) heterophase copolymer) blends was investigated by means of morphological (scanning electron microscopy), rheological (small amplitude oscillatory shear), mechanical (tensile, flexural and impact tests), and thermal (differential scanning calorimetry) properties. Compatibilizer concentration ranged from 1 to 5 wt % with respect to the whole blend. All blends were obtained in a 90/10 composition using a twin screw extruder. Compatibilization effects for PETr/PP‐EP were more pronounced due to ethylene segments present in both PP‐EP and P(E‐co‐EA‐co‐GMA). PETr/PP‐EP has shown greater dispersed phase size reduction, a more solid‐like complex viscosity behavior and larger storage modulus at low frequencies in relation to PETr/PP blend. For both investigated blends, mechanical properties indicated an improvement in both elongation at break and impact strength with increasing compatibilizer content. PETr/PP‐EP blends showed improved performance for the same level of compatibilizer content. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41892.     

Toughening polylactide with epoxidized styrene–butadiene impact resin: Mechanical,morphological, and rheological characterization

Styrene–butadiene impact resin (SBC) was chosen as the toughening agent to improve the tensile toughness of polylactide (PLA). Epoxidized SBC (ESBC) with different epoxidation degree were prepared by epoxidation using in situ peroxoformic acid method and a series of PLA/SBC(ESBC) blends were prepared by melt blending. The elongation at break of the PLA/ESBC blends was greatly improved, which was reflected in the slight decrease in the tensile strength and tensile modulus. Moreover, the tensile strength and tensile modulus were not significantly affected by the epoxidation degree of ESBC. For example, the incorporation of ESBC28.8% (30 wt %) to PLA caused an obvious increment of elongation at break from 3.5% of pure PLA to 305.0%, while the tensile modulus and tensile strength decreased to 80 and 78% of pure PLA, respectively. Scanning electron microscopy observations of cryo‐fractured surface morphology and particle size analysis demonstrated that the compatibility of the PLA/ESBC blends was improved significantly compared to PLA/SBC blend. PLA/ESBC(70/30) blends exhibited shear‐thinning behavior over the range of the studied shear rate. With an increase in shear rate, the non‐Newtonian index of the blends decreased gradually. Furthermore, the flow behavior of PLA/ESBC(70/30) blends was more sensitive to the shear rate than pure PLA. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46058.     

Miscibility enhancement of PP/PBT blends with a side‐chain liquid crystalline ionomer

Side‐chain liquid crystalline ionomer (SLCI) containing sulfonic acid groups with a polymethylhydrosiloxane main‐chain was used in the blends of polypropylene (PP) and polybutylene terephthalate (PBT) as a compatibilizer. The crystalline behavior, morphological, and mechanical properties of the blends were investigated in detail by differential scanning calorimetry (DSC), polarizing optical microscope (POM), Fourier transforms infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Revealed by the shift of T_m in DSC thermogram and the shift of the absorbed peak in FTIR spectra, specific interaction led to stronger interfacial adhesion between these phases, which resulted in much finer dispersion of the minor PBT phase in PP matrix. The SLCI containing sulfonate acid groups acted as physical crosslinking agent along the interface, which compatibilized PP/PBT blends. The mechanical property of the blends including 4 wt % SLCI contents was better than that of other SLCI contents in the blends. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effects of molecular weight and grafted maleic anhydride of functionalized polylactic acid used in reactive compatibilized binary and ternary blends of polylactic acid and thermoplastic cassava starch

Polylactic acid (PLA) was reactively functionalized with maleic anhydride (MA) and 2,5‐bis(tert‐butylperoxy)?2,5‐dimethylhexane (Luperox 101 or L101) using a twin screw extruder (TSE). The effects of functionality (grafted MA level) and/or number average molecular weight of functionalized PLA (PLA‐g‐MA) as the reactive polymer pairs (binary blends) and reactive compatibilizer (ternary blends) were investigated. Due to the dominant side reaction during melt free radical grafting, polymer degradation or chain scission, PLA‐g‐MA having a higher grafted MA had lower molecular weights and intrinsic viscosity as well as broader molecular weight distribution values. The thermal, physical, mechanical, and morphological properties of binary blends produced by using the TSE and injection molding at a ratio of 70 wt % PLA‐g‐MA and 30 wt % thermoplastic cassava starch (TPCS) were analyzed. The reactive blends having grafted MA more than 0.4 wt % had poor tensile strength and elongation at break. Similar trends in morphology and tensile properties were observed in the reactive ternary blends. The use of PLA‐g‐MA strongly impacted the elongation at break but not the modulus or tensile strength. An increase of PLA‐g‐MA's number average molecular weight ( or M_n) improved the tensile properties of the blends. The reactive ternary blend having 0.1 wt % grafted MA on PLA and PLA‐g‐MA basis and PLA‐g‐MA's M_n of 45 kDa offered the highest elongation at break. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42230.     

Thermal,morphological, and mechanical characteristics of polypropylene/polybutylene terephthalate blends with a liquid crystalline polymer or ionomer

Thermotropic side‐chain liquid crystalline polymer (SLCP) and corresponding side‐chain liquid crystalline ionomer (SLCI) containing sulfonate acid were used in the blends of polypropylene (PP) and polybutylene terephthalate (PBT) by melt‐mixing respectively, and thermal behavior, morphological, and mechanical properties of two series of blends were investigated by differential scanning calorimetry, Fourier transforms infrared spectroscopy (FTIR), scanning electron microscopy, and tensile measurement. Compared with the immiscible phase behavior of PP/PBT/SLCP blends, SLCI containing sulfonate acid groups act as a physical compatibilizer along the interface and compatibilize PP/PBT blends. FTIR analyses identify specific intermolecular interaction between sulfonate acid groups and PBT, and then result in stronger interfacial adhesion between these phases and much finer dispersion of minor PBT phase in PP matrix. The mechanical property of the blend containing 4.0 wt % SLCI was better than that of the other blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4712–4719, 2006     

Bio‐based diblock copolymers prepared from poly(lactic acid) and natural rubber

New bio‐based diblock copolymers were synthesized from poly(lactic acid) (PLA) and natural rubber (NR). NR polymer chains were modified to obtain hydroxyl telechelic natural rubber oligomers (HTNR). Condensation polymerization between PLA and HTNR was performed at 110°C during 24 or 48 h. The molecular weight of PLA and HTNR and the molar ratio PLA : HTNR were varied. The new ester linkage in the diblock copolymers was determined by ¹H‐NMR. The molecular weight of the diblock copolymers determined from SEC agreed with that expected from calculation. The thermal behavior and degradation temperature were determined by DSC and TGA, respectively. The diblock copolymers were used as a toughening agent of PLA and as a compatibilizer of the PLA/NR blend. PLA blended with the diblock copolymer showed higher impact strength, which was comparable to the one of a PLA/NR blend. The former blend showed smaller dispersed particles as showed by SEM images, indicating the increase in miscibility in the blend due to the PLA block. The compatibilization was effective in the blends containing ～10 wt % of rubber. At a higher rubber content (>10 wt %), coalescence of the NR and diblock copolymer was responsible of the larger rubber diameter in the blends, which causes a decrease of the impact strength. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41426.     

Toughness of ABS/PBT blends: The relationship between composition,morphology, and fracture behavior

A series of acrylonitrile–butadiene–styrene (ABS) copolymer/poly(butylene terephthalate) (PBT)/acrylonitrile‐styrene‐glycidyl methacrylate (ASG) blends with various compositions were prepared and characterized in this study. When the fraction of ABS exceeds a critical value there is a rapid increase in notched impact strength of ABS/PBT blends no matter whether the compatibilizer ASG is present. By combining morphology observation and notched impact results, we found that the ductile‐brittle transition of the blends is closely related to the morphology inversion. The notched impact strength jumps from 15.9 to 33.4 kJ/m² when phase inversion of ABS occurs at its fraction of 58 wt %. Accordingly, a possible toughening mechanism involved in the blends is proposed on the basis of a careful analysis of fracture energy, crack propagation behavior and fracture surface morphology. It is believed that the continuous ABS phase plays the critical role in toughening ABS/PBT blends. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46051.     

Effects of hetero-armed star-shaped PCL-PLA polymers with POSS core on thermal,mechanical, and morphological properties of PLA

In this study, AB type-heteroarm star-shaped poly(ε-caprolactone)-poly(lactic acid) (PCL-PLA) polymers with polyhedral oligomeric silsesquioxane (POSS) core ((PCL)₄-POSS-(PLA)₄, coded as SPLA) were synthesized successfully by using ring opening polymerization and click chemistry techniques together. The synthesized polymers were compounded with commercial PLA at different blending ratios (PLA/SPLA = 100/0, 95/5, 90/10, and 80/20% wt). The effects of heteroarm SPLA polymers having different arm lengths (n = 10, 20, 30, and 50) on morphological, mechanical, and thermal behaviors of PLA were investigated. It is determined that SPLA polymers with four PLA and four PCL arms on its structure enhanced mechanical properties of PLA. The tensile modulus decreased, and lowest modulus values were observed with blends prepared at 80/20 ratio. Elongation at break values increased in all blends, maximum increment was observed with 1,4-phenylene diisocyanate (PDI) containing SPLA20 blends prepared at 90/10 ratio. This result showed that SPLA20 had optimum chain length for chain extension reactions of between PLA chains. Besides, a trade compatibilizer PDI was utilized to enhance the intercompatibility of binary polymer blends.     

Study on in situ reinforcing and toughening of a semiflexible thermotropic copolyesteramide in PBT/PA66 blends

Ternary in situ composites based on poly(butylene terephthalate) (PBT), polyamide 66 (PA66), and semixflexible liquid crystalline polymer (LCP) were systematically investigated. The LCP used was an ABA30/PET liquid crystalline copolyesteramide based on 30 mol % of p‐aminobenzoic acid (ABA) and 70 mol % of poly(ethylene terephthalate) (PET). The specimens for thermal and rheological measurements were prepared by batch mixing, while samples for mechanical tests were prepared by injection molding. The results showed that the melting temperatures of the PBT and PA66 phases tend to decrease with increasing LCP addition. They also shifted toward each other due to the compatibilization of the LCP. The torque measurements showed that the ternary blends exhibited an apparent maximum near 2.5–5 wt % LCP. Thereafter, the viscosity of the blends decreased dramatically at higher LCP concentrations. Furthermore, the torque curves versus the PA66 composition showed that the binary PBT/PA66 blends can be classified as negative deviation blends (NDBs). The PBT/PA66/LCP blends containing up to 15 wt % LCP were termed as positive deviation blends (PDBs), while the blends with the LCP ≥25 wt % exhibited an NDB behavior. Finally, the tensile tests showed that the stiffness and tensile strength of ternary in situ composites were generally improved with increasing LCP content. The impact strength of ternary composites initially increased by the LCP addition, then deteriorated when the LCP content was higher than 10 wt %. The correlation between the mechanical properties and morphology of the blends is discussed. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1975–1988, 2000     

Miscible blends of biobased poly(lactide) with poly(methyl methacrylate): Effects of chopped glass fiber incorporation

Poly(lactide) (PLA) and poly(methyl methacrylate) (PMMA) are melt compounded with chopped glass fiber using laboratory scale twin‐screw extrusion. Physical properties are examined using differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), thermogravimetric analysis (TGA), tensile testing, impact testing, X‐ray computed tomography (CT) scanning, and field emission scanning electron microscopy (FE‐SEM). Molecular weight is determined using gel permeation chromatography (GPC). Miscibility of the blends is implied by the presence of a single glass transition temperature and homogeneous morphology. PLA/PMMA blends tend to show positive deviations from a simple linear mixing rule in their mechanical properties (e.g., tensile toughness, modulus, and stress at break). The addition of 40 wt % glass fiber to the system dramatically increases physical properties. Across all blend compositions, the tensile modulus increases from roughly 3 GPa to roughly 10 GPa. Estimated heat distortion temperatures (HDTs) are also greatly enhanced; the pure PLA sample HDT increases from 75 °C to 135 °C. Fiber filled polymer blends represent a sustainable class of earth abundant materials which should prove useful across a range of applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44868.