Polyolefins containing high purity polyhedral oligomeric silsesquioxanes

Abstract

The use of high-purity polyhedral oligomeric silsesquioxanes (POSS) additives at ppm loading levels to impact the physical properties of polyolefins. At these loading levels, POSS additives improve the melt strength of polyolefins by transferring stress between the polyolefin chains, and thus reduce or eliminate melt fracture. While increasing the strength of the melt, the POSS additives also disentangle the polyolefin chains and thus increase the rheological flow. The POSS additives also increase the surface energy and adhesion strength of polyolefins, thereby eliminating the need for wetting of the polyolefin.

Description

POLYOLEFINS CONTAINING HIGH PURITY POLYHEDRAL OLIGOMERIC SILSESQUIOXANES CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of and priority to U.S. ProvisionalApplication No.63 / 708,126, filed October 16, 2024, which is incorporated by reference herein in its entirety. BACKGROUND

[0002] Polyhedral oligomeric silsesquioxanes (POSS® - Hybrid Plastic, Inc.)are a family of molecules that consist of a silica-like core surrounded by a shell of organic groups. The chemical composition of POSS is a hybrid intermediate between that of silica (SiO2) and silicone (R2SiO). Silsesquioxane is the IUPAC name for a range of polycyclic compounds consisting of a hydrocarbon, a silicon, and an average of 1.5 oxygen atoms (RSiO1.5). The name silsesquioxane is derived from siloxane where sil denotes silicon, sesqui (Latin meaning one and a half) and where sesquioxane denotes an average of 1.5 oxygens per silicon atom, while ane denotes that each silicon is also attached to an organic group. The words polyhedral and oligomeric denote their rigid 3-d shape / topology and their intermediate sizes (0.5-3.0nm) being between that of monomers and polymers.

[0003] The key purpose of POSS as an additive is to enable polymercompositions that process more easily and display new or enhanced physical characteristics imparted by the cage. Generically, POSS cages have the empirical formula (RSiO1.5)n, where R is an important organic group such as an alkyl, alkylene, acrylate, hydroxyl, amine, epoxide, peg, aromatics or other chemically relevant functional group. Unlike organic modified silica, or clays, POSS are well defined chemical molecules that are soluble and compatible with the amorphous regions of polymeric chains.

[0004] Global production of polymers increased to 390.7 million tons in 2021.The largest part of which is made up of polyolefins. It is estimated that approximately 105 million tons of polyethylene (PE) and 75 million tons of polypropylene (PP) were produced worldwide in 2021 in total, covering 46.2% of global plastics production.1Meanwhile, in the 1950s, the market share of polyolefins was negligible. The commercial production of polyolefins was enabled by the discovery of organometallic 1 #110059902v4catalysts. Refinement of these catalysts evolved the rational design of polyolefins into motifs described as linear low density (LLD), low density (LD), high density (HD), and ultrahigh molecular weight (UHMW) polyethylene and copolymers thereof with specialized utility.

[0005] Over the past two decades, there has been an increase in researchexploring polyolefin polymers containing a cage-like additives. Discernment of this literature requires a distinction of the type of polyolefin and the type of cage additive. Without recognizing these distinctions many of the effects reported would seem contradictory.

[0006] In 2023, Czaja et al. reviewed the methods for incorporating POSS-typeadditives into polyolefins, as a catalyst, a comonomer, crosslinker, and a blendable filler.2They state that organic groups on the cage can enhance or decrease polyolefin properties such as crystallinity, plasticization, thermal stability, and flammability. Interactions between the cage and other additives commonly used in polyolefins such as sorbitols can also occur and influence properties. The review concludes that correlations between the microscopic and macroscopic properties of polyolefin / POSS nanocomposites, has not been fully resolved.

[0007] Lichtenhan et al. in U.S. Patent No. 6,716,919 described the earliestfindings for the incorporation of POSS additives in a polyolefin. Specifically, the methods for compounding them into polymers to create nano-alloyed polymers. At that time, it was postulated that incorporation of these cage additives would enhance specific regions of the polymer. In turn this would lead to the improvement of time-dependent mechanical and thermal properties. Using polypropylene (PP) and i-butyl POSS at loading levels of 2-10 wt%, direct evidence was provided to support viscosity reduction, enhanced tensile and flexural modulus, heat distortion, and Izod impact improvements. USP 6,716,919 however did not provide evidence to support adhesion, nor melt strength enhancements.

[0008] Fu et al. studied the interactions between an octamethyl POSS and PP at10-30 wt % loadings, finding that at these high loading levels the rate of polymer crystallization increased.3Niemczyku et al. studied PP containing 1-10 wt% spherosilicate cages bearing alkylsiloxy groups. They found the cages reduced the degree of crystallinity and provided plasticization which increased the melt flow rate and reduced desirable mechanical properties.4In a related publication, Niemczyku et al. studied LDPE and HDPE containing 1-10 wt% spherosilicate cages bearing 2 #110059902v4alkylsiloxy groups. They found cage incorporation enhanced rheological melt flow rate, and the cages alters the free-volume properties and crystallinity of polyethylene matrices. At low additive levels, cages occupy free volumes, while higher loadings lead to increased free volumes due to aggregation. Consequently, spherosilicate-cage- LDPE-based nanocomposites, showed increased tensile strength, elongation at break and Charpy impact strength for 1 wt % cage compositions.

[0009] Panaitescu et al, incorporated alkylsiloxyspherosilicate cages at loadinglevels of 0.5-1wt% and found an improvement of lower melt viscosity, without influence on PE crystallinity. Panaitescu et al also observed a favorable increase of tensile strain and energy of break.5The improvement of energy at break provides indirect support that melt strength might be enhanced from POSS-type additives. However, tensile measurements are conducted only at a single temperature (usually room temperature) and they do not infer characteristics across a spectrum of temperatures and strain rates as would be necessary for melt strength enhancement.

[0010] Brzakalski et al, investigated the use of silsesquioxane derivatives asfunctional additives in polyethylene composites.6The research examined 0.1-1.5 wt% loading levels of alkylsilsesquioxane, heptaisobutyl cages containing one unique monoalkyl group, and alkylsilicate additives. Notably the octa-isobutyl POSS was not examined. All systems improved the rheological melt flow rate and at higher loadings became plasticizing. All POSS additives were found to enhance the thermal stability of PE in air. The compositions also exhibited higher Young’s modulus and small improvements of tensile strength compared to neat PE. Some compositions, depending on cage-organic group, promoted the nucleation of PE and HDT.

[0011] Lim et al, examined octamethyl, octaisobutyl, and octaphenyl POSS ina low molecular weight PE (Mn = 7.7k, Mw = 35k) at 0.5 %, 1 wt%, and 2 wt% loading levels.7As with other researchers POSS incorporation provided enhanced thermal stability, tensile strength, and elongation at break. The octaisobutyl POSS additive was especially effective. These enhancements were attributed to the favorable interaction between the PE chain and the octaisobutyl cage additive.

[0012] Hato et al, examined LLDPE containing 5%, 7.5% and 10 wt%octamethyl POSS.8They found that were POSS micro-aggregates significantly enhance the properties of LLDPE nanocomposites because they provided multiple melting behaviors observed via DSC. The partial melting and re-crystallization phenomena influenced physical properties. 3 #110059902v4

[0013] Romo-Uribe et al studied LDPE containing 0.5-10 wt% octaisobutylPOSS cages.9A material science theory for POSS-PE chain interactions was developed that correlated the size of octaisobutyl POSS cages (∼1.5 nm) to the entanglement mesh size (∼3.28 nm) of the PE chains. When the cage melts, and when its primary size is smaller than the distance between PE entanglements (a mesh) rheological reduction occurs and cages disentangle the PE chains. Fundamentally such a relationship facilitates viscosity reduction. At low concentrations, POSS cages fills spaces within the entangled network, enhancing barrier properties and other time dependent properties. The opposite happens when cages exceed the solubility or percolation limit of PE. In such cases barrier properties decline due to cages aggregating into crystalline clusters and creating vacancies within the PE mesh.

[0014] In 2020 Romo-Uribe and Lichtenhan specifically focused on LLDPEand LDPE blends as these are often utilized together in packaging film. Tiny amounts of cages 80-400 ppm (parts per million) were utilized as these levels would provide an economical use case for the cage additives. At ultra low 80-400 ppm levels octaisobutyl and octamethyl cage compositions were both found to significantly enhance the mechanical properties (puncture resistance, tensile strength, modulus, elongation), decomposition temperatures and barrier properties of polyethylene (PE) and blends. Specifically, puncture resistance, was improved and was maximized when the cage- particle size matched the polymers tube reptation diameter. This improvement was maintained even after films were aged 18 months at room temperature, demonstrating the durability of the enhancement. They also reported that incorporation of either octaisobutyl or octamethyl resulted in lower surface energy (higher hydrophobicity) as evidenced by water contact angle measurements. This change in surface energy could potentially reduce adhesion, to polar surfaces or substances. Finally, Romo-Uribe and Lichtenhan viewed octaisobutyl more favorably because of its higher compatibility and rapid dispersion characteristics.10

[0015] The research has focused on the effects of POSS nanocage and othercage (e.g., alkylsiloxy spherosilicate or MQ silicone) additives on viscosity, crystallinity, tensile and flexural modulus, and thermal stability of polyolefins. However, the prior art has not recognized or adequately addressed the role of parts-per- million (ppm) concentrations of polyhedral oligomeric silsesquioxane (POSS) in influencing the properties of polyolefins. 4 #110059902v4SUMMARY OF THE INVENTION

[0016] Disclosed herein are POSS-modified polyolefin compositions andimproved processes for manufacturing polyolefins with polyhedral oligomeric silsesquioxanes.

[0017] In one aspect of the present invention, it has been discovered that theutilization of POSS nanochemical additives at 250-800 ppm load levels improves the melt strength of the resultant POSS-modified polyolefin composition by transferring stress between the polyolefin chains, thus reducing or eliminating melt fracture during manufacturing of polyolefin films. The enhanced melt strength of the POSS / polyolefin composition results in improved processability of the polyolefin and increased mechanical properties of the resulting product.

[0018] In yet another aspect of the present invention, it has been discovered thatthe POSS additives disentangle the polyolefin while either increasing or decreasing the modulus of the polyolefin, resulting in a polymer and POSS composition with improved rheological flow and increased stiffness of the melt.

[0019] In yet another aspect of the present invention, it has been discovered thatthe POSS additives increase surface energy and thus enhance adhesion between polyolefins and solid surfaces. This results in increased lap-shear strength in olefinic adhesives and eliminates the need to wet the polyolefins.

[0020] These criteria lend themselves toward the use of high purity homoleptic[(i-ButylSiO1.5)8]^8 and isobutyl POSS related heteroleptic cages [(R1SiO1.5)x(R2SiO1.5)y(R3SiO1.5)z]^x+y+z at 250-800 ppm load levels as replacements for fluorinated processing aids (e.g., PFAS) and other polyolefin processing additives, which are commonly added to polyolefin compositions used in film and packaging. BREIF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying figures, together with the detailed description below,are incorporated in and form part of the specification, serve to illustrate further various exemplary embodiments and to explain various principles and advantages in accordance with the present invention:

[0022] Figure 1 is a graphical representation of differential scanningcalorimetry (DSC) of high-purity i-butyl POSS [(i-BuSiO1.5)8]^8 and linear low-density polyethylene (LLDPE). 5 #110059902v4

[0023] Figure 2 is an illustration of representative cage compositions of phenylhomoleptic decamer and phenyl, methyl, vinyl heteroleptic octamer, as well as melting, solubility, and use characteristics of the representative cage compositions.

[0024] Figure 3 is a graphical representation of melt viscosity relative totemperature for heteroleptic POSS [(PhSiO1.5)3(ViSiO1.5)3(MeSiO1.5)2]^8.

[0025] Figure 4 is a graphical representation of complex viscosity relative toangular frequency for low molecular weight LLDPE and high molecular weight LLDPE.

[0026] Figure 5 is a graphical representation of storage modulus (G’), lossmodulus (G”), and cross-over point relative to angular frequency for low molecular weight LLDPE and high molecular weight LLDPE.

[0027] Figure 6 is a graphical representation of storage modulus (G’), lossmodulus (G”), and cross-over point relative to angular frequency for high molecular weight LLDPE, 250 ppm i-Bu POSS [(i-BuSiO1.5)8]^8 in high molecular weight LLDPE, and 500 ppm i-Bu POSS [(i-BuSiO1.5)8]^8 in high molecular weight LLDPE.

[0028] Figure 7 is a graphical representation of storage modulus (G’), lossmodulus (G”), and cross-over point relative to angular frequency for low molecular weight LLDPE, 250 ppm i-Bu POSS [(i-BuSiO1.5)8]^8 in low molecular weight LLDPE, and 500 ppm i-Bu POSS [(i-BuSiO1.5)8]^8 in low molecular weight LLDPE.

[0029] Figure 8 is a graphical representation of extensional viscosity relative toHencky strain for i-Bu POSS [(i-BuSiO1.5)8]^8 concentrations of 0 ppm, 80 ppm, and 400 ppm in polyolefin films at 125°C.

[0030] Figure 9 is a graphical representation of storage modulus (G’) forLLDPE, 500 ppm i-Bu POSS [(i-BuSiO1.5)8]^8 in LLDPE, and 500 ppm phenyl POSS in LLDPE. [PhSiO1.5)12]^12. DETAILED DESCRIPTION OF THE INVENTION

[0031] Detailed embodiments of the present invention are disclosed herein.However, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed 6 #110059902v4structure. Alternate embodiments may be devised without departing from the spirit or the scope of the invention. Further, the terms and phrases used herein are not intended to be limiting, but rather, to provide an understandable description of the invention. While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the drawing figures, in which like reference numerals are carried forward.

[0032] For the purposes of understanding this invention's chemicalcompositions, the following definition for formula representations of POSS are provided.

[0033] Polysilsesquioxanes are materials represented by the formula [RSiO1.5]nwhere n represents molar degree of polymerization and R represents organic substituents (H, siloxy, cyclic, aliphatic, olefinic, aromatic, or such organic groups that may additionally contain reactive functionalities such as alcohols, isocyanates, esters, amines, ketones, olefins, ethers, mercapto, peg, or halides) or nonreactive groups such as silicones, halogens, phosphazines. Polysilsesquioxanes may be either homoleptic or heteroleptic. Homoleptic systems contain only one type of R group, while heteroleptic systems contain more than one type of R group (R1,2,3 etc.) distributed in a statistically random manner on a distribution of cage cores ranging from 8-14 (^x+y+z).

[0034] POSS nanostructure compositions are represented by the formula:[(RSiO1.5)x]^# for homoleptic compositions [(RSiO1.5)x(R1SiO1.5)y(R2SiO1.5)z]^# for heteroleptic compositions (where R ^ R1,2)The symbols x and y refer to the stoichiometry of the composition and can include multiple different (RSiO1.5)zcomponents. The symbol ^ indicates that the composition forms a well-defined nanostructure and the symbol # refers to the number of silicon atoms contained within the nanostructure. The value for # is the sum of x+y, where it typically from 1 to 24. It should be noted that ^# is not to be confused as a multiplier for determining stoichiometry, as it merely describes the overall nanostructural characteristics of the system (aka cage size).

[0035] In particular, i-butyl POSS [(i-BuSiO1.5)8]^8 is well positioned as areplacement for PFAS in polyolefin processing. Intriguingly, i-butyl POSS [(i- BuSiO1.5)8]^8 is known to have a similar coefficient of friction to that of 7 #110059902v4polytetrafluoroethylene (PTFE), despite not containing any fluorine atoms. Prior art describing the preparation of i-butyl POSS has been disclosed in U.S. Patent No. 6,972,312.11The melting point of [(i-BuSiO1.5)8]^8 is advantageous for polyolefin applications. Specifically, high-purity [(i-BuSiO1.5)8]^8 shows thermal transitions at ~61°C and ~265°C, as indicated in Figure 1. The melting point of [(i-BuSiO1.5)8]^8 is similar to that of polyolefins, which is desirable as it enables the POSS to become more readily mixed, solubilized, and effectively placed between the polymer chains.

[0036] Variation of the organic i-butyl groups on [(i-BuSiO1.5)8]^8 may also beadvantageous. For example, heteroleptic cages bearing i-butyl and small molar amounts of different silanes (such as vinyl, octyl, i-octyl, phenyl, methyl) can be desirable depending on the co-ter-polymer compositions or in the event the polyolefin is blended with other polymer types (such a nylons, polylactic acid, etc.). Heteroleptic cages containing two or more organic functionalities within the same cage composition are distributed in a statistically random manner on the cage. See PCT Application No. PCT / US21 / 21715 for elucidation of heteroleptics containing a wide variety of organic group combinations on the cage12and recent coating publications using heteroleptics.13An advantage of i-butyl-based heteroleptics is the incorporation of a second organic functionality on the cagecan be used to depress or increase the cage melting point.

[0037] With reference to Figure 2 and to illustrate the impact of composition onthe melting point and solubility of POSS, a representative structure of an all phenyl dodecamer (homoleptic) cage melts at 364°C, while a related heteroleptic composition bearing three phenyl, three vinyl, and two methyl groups melts at 150°C, which is very close to the melting point range of polyolefins (~130 °C average).

[0038] As shown in Figure 4, POSS cages show a lower viscosity upon meltingthan most polymers and effectively reduce the extruder torque, barrel pressure, and melt viscosity. This is advantageous during the melt processing of polyolefins as barrel / die pressures must be maintained at safe levels and the torque of extruders (polymer- pumps) are limited.

[0039] Heteroleptics of i-butyl with 1-2 molar equivalents of vinyl (or a relatedolefin) as shown in in Figure 2 are well suited for use as secondary crosslink points, which can be produced using peroxide or e-beam cure.14The crosslinking of polyolefins is common to improve durability and flammability of wire coatings. In a related manner, i-butyl / i-octyl or n-octyl heteroleptics may be of great utility in countering the 8 #110059902v4embrittlement effects common to polyolefins during sterilization by gamma radiation.15Finally, the incorporation of [(i-BuSiO1.5)8]^8 and i-butyl heteroleptic POSS compositions can serve to reduce the interfacial tension between blends of polyolefins with other commodity or engineering resins, which are usually of higher polarity.16EXAMPLES Example 1: Effect of i-butyl homoleptic POSS on Extruder Torque and Pressure on Low MWT LLDPE.

[0040] The effect of adding [(i-BuSiO1.5)8]^8 is immediately evident to theprocessor due to a significant reduction of extruder torque and barrel pressure when processing both high and low molecular weight LLDPE grades, as shown in Table 1. The reduction of torque and pressure is more pronounced in high molecular weight LLDPE than in lower molecular weight grades. As the loading level of [(i- BuSiO1.5)8]^8 is increased from the 250-2000 ppm, the diluent effect becomes more pronounced. Table 1. Effect of POSS addition on torque and barrel pressure. Property LLDPE + 250 ppm + 500 ppm + 2000 ppm (control) [(i- [(i-BuSiO15)8]^8 [(i-Example 2: Polyolefin Viscosity and Entanglements.

[0041] LLDPE is manufactured in a wide range of molecular weights. Theseare rheologically distinguishable. Figure 4 is a plot of complex viscosity (@160°C) relative to oscillation frequency, which shows a higher complex viscosity for higher molecular weight PE than for the lower molecular weight grade across all frequencies.

[0042] Equally distinguishing is the entanglement molecular weight where atthe "crossover point" the elastic (storage) modulus (G') and viscous (loss) modulus (G'') are equal, indicating the point of maximum entanglement and loss of elasticity in the polymer melt. The crossover indicates a balance between elastic and viscous behavior. Thus, at frequencies above the crossover point, the material is more solid-like (higher 9 #110059902v4G'), which can contribute to higher melt strength. At frequencies below the crossover point, the material behaves more like a viscous fluid (higher G"), which can lead to lower melt strength. For high molecular weight LLDPE, the crossover frequency is generally at lower frequencies, thereby reflecting longer entanglement chains. Conversely, low molecular weight LLDPE shows a higher crossover frequency. This is shown in Figure 5 for each of the two base resins utilized in this study. Example 3: [(i-BuSiO1.5)8]^8 added to High Mwt. polyolefin.

[0043] The effects of adding 250 and 500 ppm of [(i-BuSiO1.5)8]^8 wereevaluated in high weight commercial grade LLDPE. Because of their viscoelastic behavior, a comparison of gel-point dynamic rheology was utilized.

[0044] Figure 6 provides a data plot showing differences in cross-over points(aka gel point) for 250 and 500 ppm of [(i-BuSiO1.5)8]^8 in high molecular weight LLDPE relative to the control LLDPE. Specifically, the gel point is (14.3 rad / sec) for LLDPE, (15.5 rad / sec) for the 250-ppm formulation, and (15.7 rad / s) for the 500-ppm formulation. This is also accompanied by a 10.83% increase in modulus for the 250- ppm formulation and a 9.96% increase in modulus for the 500-ppm formulation. The interpretation supports the disentanglement of the polymer chains by the [(i- BuSiO1.5)8]^8 and improvement of its rheological flow while increasing the stiffness of the melt. Based on the modulus values, a 250-ppm loading of [(i-BuSiO1.5)8]^8 in high molecular weight LLDPE appears to be superior to a 500-ppm loading. Example 4: [(i-BuSiO1.5)8]^8 added to Low Mwt. polyolefin.

[0045] In a complimentary manner, 250 and 500 ppm of [(i-BuSiO1.5)8]^8 wasevaluated in low molecular weight commercial grade LLDPE. Figure 7 shows a similar disentanglement effect wherein the cross over frequency was shifted to a higher value. Specifically, the gel point is (33.4 rad / sec) for LLDPE, (34.3 rad / sec) for the 250-ppm formulation, and (34.3 rad / s) for the 500-ppm formulation. This is also accompanied by a 15.79% decrease in modulus for the 250-ppm formulation and a 3.53% decrease in modulus for the 500-ppm formulation. Based on the modulus values, a 500-ppm loading of [(i-BuSiO1.5)8]^8 in low molecular weight LLDPE appears to be superior to a 250-ppm loading. 10 #110059902v4Example 5: Melt strength via Extensional Rheology.

[0046] Melt strength is perhaps the most important rheological parameter forfilm and fiber manufacture. It can be described as the resistance of the polymer melt to stretching. The melt strength of a material is related to chain entanglements and their resistance to untangling under strain. Extensional rheology simulates the stretching and pulling processes that polymer melts experience during real-world manufacturing. It can also operate at a temperature closer to the transitional liquid-rubber-solid transitional regions, thus enabling melt strength to be examined over the region where film formation originates and thereby determine elongational flow stability. Melt fracture in polyolefins occurs when polymer chains are stretched under tension during film blowing as the polymer cools.17The presence of fluoropolymers within the polymer and at the die surface aids in reducing entrapped stress.

[0047] With these understandings of stress transfer and energy dissipationthrough interfacial domains, extensional rheology was used to determine the effect of ppm levels of i-butyl POSS on polyolefin films. The results are shown in Figure 8, which clearly show the correlation of increased i-butyl POSS to increased melt strength. Thus, the strain-to-fracture of the molten polyethylene is higher (tougher) because of the presence of [(i-BuSiO1.5)8]^8. This buildup of extensional viscosity points to increased molecular friction and improved stress transfer to the PE chains via the i- butyl nanocages. An analogy would be the use of these non-covalently bound cages to couple more PE polymer chains together to respond to the applied stretching force. Example 6: Modulus Recovery from the Melt via Dynamic Mechanical Rheology.

[0048] The ability of POSS containing LLDPE to regain their modulus duringthe melt-to-rubber-to-solid transition (during cooling) was then examined. Figure 9 provides a DMA plot showing storage modulus recovery as a function of temperature for LLDPE, LLDPE+500 ppm i-butyl POSS [(i-BuSiO1.5)8]^8, and LLDPE+500 ppm phenyl POSS [(PhSiO1.5)12]^12.

[0049] Examination of the i-butyl POSS relative to the LLDPE reveals the onsetand rate of modulus buildup (recovery) occurs earlier for the 500 ppm i-butyl POSS system than for the control. It is conceivable the rate of solidification has been aided by the dissipation capability of the nanocage and perhaps by associative coupling. Favorably, the level of storage modulus reached is also higher than for the control. 11 #110059902v4Thus, one would anticipate higher melt strength and fast realization of melt strength (fracture elimination) during film formation.

[0050] A stark contrast, however, is observed for the 500-ppm phenyl POSS(red trace). In this case, the phenyl groups on the cage are poorly compatible with polyolefins. Hence, the phenyl cages do not couple to the polymer chains sufficiently to dissipate energy and rebuild modulus.

[0051] Interestingly, DSC cooling scans of LLDPE and that containing ppmlevels of POSS do not show any significant changes in the recrystallization enthalpy or the peak temperature relative to the control. Thus, the DSC findings would not have led one to anticipate such a discovery. Example 7: Effect of i-butyl homoleptic POSS on adhesive strength on a polyolefin.

[0052] In this study a 0.25g of polymer was melt pressed (at 180°C under 2kgof force) into a 2.54 cm square area between two overlapping rigid aluminum rectangles 12.7 cm in length. Upon cooling to room temperature, a lap-shear tensile test was carried out at room temperature (22 °C). In all cases, adhesive failure was observed. Table 2 provides summarized findings for high Mwt LLDPE, and Table 3 provides summarized findings for low Mwt LLDPE. Thus, despite the supposition one may have drawn of reduced adhesion from earlier literature reporting enhanced hydrophobicity, this is not the case. The incorporation of ppm levels of [(i-BuSiO1.5)8]^8 resulted in a pronounced enhancement of adhesion. Table 2. Adhesive Strength for high Mwt LLDPE with and w / o POSS. High Mwt + 250 ppm + 500 ppm Pr rt LLDPE 8a e . es ve reng or ow w w an w / o . Low Mwt + 250 ppm + 500 ppm 812 #110059902v4

[0053] Lap shear adhesion was tested in a similar manner using woodmeasuring 14 cm with a 1.7 cm square overlap. The findings for high molecular weight LLDPE are tabulated below in Table 4. Again, a pronounced enhancement of adhesion was observed. Table 4. Adhesive Strength for high Mwt LLDPE with and w / o POSS. High Mwt + 250 ppm + 500 ppm + 2000 ppm Property LLDPE [(i-B SiO ) ]^8 [(i-B SiO ) ]^8 [(PEG10SiO ) ]^8xamp e : ec o - u y on ur ace nergy

[0054] The surface energy resulting from ppm levels of [(i-BuSiO1.5)8]^8 intoLLDPE was next assessed using dyne pen measurements. As shown in Table 5, the surface energy of LLDE does not appreciably change upon inclusion of 250 and 500 ppm amounts of cages. Higher loading levels do result in an increase of surface energy. Table 5. Surface Energy via addition of i-butyl cage. LLDPE (control) + 500 ppm + 2,000 ppm + 20,000 ppm 8

[0055] Polyolefins are frequently utilized in extrusion lamination and extrusioncoating processes. In these processes, a molten polyolefin is bonded against a second surface which can be a film or a more substantial surface such as wood, composite, glass, etc. Wet-out of the polyolefin against the second surface is required for good bond strengths.

[0056] The inherently low surface energies of polyolefins often require surfacemodification to bond adequately to higher surface energy substances. Industrially, converters use in-line treatment processes such a Corona, Flame, or Plasma to oxidize the polyolefin surface and increase its surface energy, polarity. However, the use of heteroleptic cages containing iso-butyl arms for polyolefin compatibility and polar arms 13 #110059902v4peg, amine, epoxy, acrylics etc. may eliminate the need for secondary surface oxidation processes.

[0057] An additional consideration for the use of POSS additives is thatpolyolefins manufactured using Ziegler Natta (Z-N) catalysts are known to show lower adhesive strength than those manufactured via homogeneous metallocene catalysts. While the surface energy of each is the same, the adhesion strength differences are attributed to the lower viscosity and lower entanglement of chains produced via the metallocene process. The findings for POSS cage additives therefore suggest their potential utility to upgrade the adhesion of Z-N produced polyolefins to the level of higher cost metallocene polyolefins. 14 #110059902v41Plastics—The Facts 2022. Plastics Europe. Available online: https: / / plasticseurope.org / knowledge- hub / plastics-the-facts-2022 / 2“Application of Silsesquioxanes in the Preparation of Polyolefin-Based Materials,” M. Białek, K. Czaja., Materials 2023, 16, 1876. https: / / doi.org / 10.3390 / ma16051876.3B. X. Fu, L. Yang, R. H. Somani, S. X. Zong, B. S. Hsiao, S. Phillips, R. Blanski, P. Ruth, Crystallization Studies of Isotactic Polypropylene Containing Nanostructured Polyhedral Oligomeric Silsesquioxane Molecules under Quiescent and Shear Conditions Journal of Polymer Science: Part B: Polymer Physics, Vol.39, 2727–2739 (2001)4A. Niemczyk1, K. Dziubek, K. Czaja, R. Szatanik, M. Szołyga, M. Dutkiewicz, B. Marciniec, Polypropylene / polyhedral oligomeric silsesquioxane nanocomposites – study of free volumes, crystallinity degree and mass flow rate DOI: dx.doi.org / 10.14314 / polimery.2016.6105D. M. Panaitescu, A. N. Frone, C. Radovici, C. Nicolaea, F. X. Perrin, “Influence of octyl substituted octakis(dimethylsiloxy) octasilsesquioxane on the morphology and thermal and mechanical properties of low density polyethylene” Polym Int 2014; 63: 228–236 DOI 10.1002 / pi.44886D. Brzakalski, R.E. Przekop, B. Sztorch, P. Jakubowska, M. Jałbrzykowski, B. Marciniec, “Silsesquioxane Derivatives as Functional Additives for Preparation of Polyethylene-Based Composites: A Case of Trisilanol Melt-Condensation”, Polymers 2020, 12, 2269; doi:10.3390 / polym12102269.7S-K. Lim, E-P. Hong, H. J. Choi, I-J. Chin, “Polyhedral oligomeric silsesquioxane and polyethylene nanocomposites and their physical characteristics” J. Ind. Eng. Chem.Vol.16, 2, 2010, pp 189-192 https: / / doi.org / 10.1016 / j.jiec.2010.01.0498M.J. Hato, S.S. Ray, A.S. Luyt, “Nanocomposites Based on Polyethylene and Polyhedral Oligomeric Silsesquioxanes, 1–Microstructure, Thermal and Thermomechanical Properties” Macromol. Mater. Eng.2008, 293, 752–762 DOI: 10.1002 / mame.200800146.9A. Romo-Uribe, A. Reyes-Mayer, M. Paredes-Pérez, J. Lichtenhan, M. Yañez-Linoe, E. Sarmiento- Bustos, “POSS driven chain disentanglements, decreased the melt viscosity and reduced O2 transmission in polyethylene’, Polymer 165, 2019, 61-71 https: / / doi.org / 10.1016 / j.polymer.2019.01.024.10Angel Romo-Uribe+, Gary Moody, Joseph D. Lichtenhan*, Sukhendu Hait, “Polyolefin Melt Strength Recovery @ ppm POSS® Levels”, Society of Petroleum Engineers Galveston, TX Proceedings 2025. https: / / www.researchgate.net / publication / 390128137_Polyolefin_Melt_Strength_Recovery_ppm_POS S_Levels11(a) US Patent Application 2010 / 0249309 (b) Y. Tang, M. Lewin, “Migration and surface modification in polypropylene (PP) / polyhedral oligomeric silsesquioxane (POSS) nanocomposites”, Polymers for Adv. Tech., (2009) 20 (1) 1-15. DOI:10.1002 / paat.122912“Heteroleptic Polyhedral Oligomeric Silsesquioxane Compositions and Method,” S. Hait, J.D. Lichtenhan in PCT US21 / 121715 (2021)13“UV Curing Behavior of Five Heteroleptic POSS Bearing Methacrylate and Glycidyl Groups and Evaluation of Their Potential for Hard Yet Flexible Coatings,” D.N. Bender, S. Hait, J.D. Lichtenhan,G. Liu, ACS Applied Polymer Materials 2022 4 (3), 1878-1889 DOI: 10.1021 / acsapm.1c0170214“Industrial Electron Beam Processing of Polyolefins,” A.J. Berejka, M.R. Cleland, R.A.Galloway, https: / / www.researchgate.net / publication / 288214988_Industrial_electron_beam_processing_of_polyol efins15“Study of the effect of gamma irradiation on polyolefins-low-density polyethylene,” J.C.M Suarez, E.E.C. Monteirio, E.B. Mano Poly. Degradation Stability, (2002) 75(1) 143-151 https: / / doi.org / 10.1016 / S0141-3910(01)00213-016“Polypropylene / polyamide 6 / POSS ternary nanocomposites: Effects of POSS nanoparticles on the compatibility,” M. Kodal, Polymer, (2016) 105, 43-50, http: / / dx.doi.org / 10.1016 / j.polymer.2016.10.02117E.B. Muliawan, S.G. Hatzikiriakos, M. Sentmanat, “Melt Fracture of Linear PE”, Intern. Polymer Processing, 200520(1) 60-67. DOI: 10.3139 / 217.1862. 15 #110059902v4

Claims

What is claimed is:

1. A composite composition, comprising:(a) a polyolefin; and(b) 250-800 ppm of a polyhedral oligomeric silsesquioxane (POSS)additive.

2. The composite composition of claim 1, wherein a melt strength of the compositecomposition is higher than a melt strength of the polyolefin.

3. The composite composition of claim 1, wherein a surface energy of thecomposite composition is higher than a surface energy of the polyolefin.

4. The composite composition of claim 1, wherein an adhesion strength of thecomposite composition is higher than an adhesion strength of the polyolefin.

5. The composite composition of claim 1, wherein a rate of modulus recovery ofthe composite composition upon cooling is higher than a rate of modulus recovery of the polyolefin upon cooling.

6. The composite composition of claim 1, wherein a modulus of the compositecomposition is higher than a modulus of the polyolefin, and wherein the POSS additive disentangles the polyolefin.

7. The composite composition of claim 6, wherein the modulus is a storagemodulus.

8. The composite composition of claim 6, wherein the modulus is a loss modulus.

9. The composite composition of claim 1, wherein a modulus of the compositecomposition is lower than a modulus of the polyolefin, and wherein the POSS additive disentangles the polyolefin.

10. The composite composition of claim 9, wherein the modulus is a storagemodulus.

11. The composite composition of claim 9, wherein the modulus is a loss modulus.

12. The composite composition of claim 1, wherein a melt fracture of the compositecomposition is lower than a melt fracture of the polyolefin.

13. The composite composition of claim 1, wherein the polyolefin comprisespolyethylene.

14. The composite composition of claim 1, wherein the polyolefin comprisespolypropylene. 16 #110059902v415. The composite composition of claim 1, wherein the polyolefin materialcomprises polylactic acid.

16. The composite composition of claim 1, wherein the polyolefin materialcomprises nylon.

17. The composite composition of claim 1, wherein the POSS additive compriseshomoleptic POSS.

18. The composite composition of claim 1, wherein the POSS additive comprisesheteroleptic POSS.

19. The composite composition of claim 1, wherein the POSS comprises i-butylPOSS.

20. The composite composition of claim 1, wherein the POSS comprises phenylPOSS.

21. The composite composition of claim 1, wherein the POSS comprises a silaneselected from the group consisting of i-butyl, vinyl, octyl, i-octyl, phenyl, and methyl.

22. The composite composition of claim 1, wherein the POSS additive has theformula [RSiO1.5]n, wherein n represents molar degree of polymerization and R represents organic substituent.

23. The composite composition of claim 22, wherein the organic substituent isselected from the group consisting of hydrogen, siloxy, cyclic, aliphatic, olefinic, aromatic, alcohol, isocyanates, esters, amines, ketones, ethers, mercapto, peg, halide, silicone, halogen, and phosphazine.

24. The composite composition of claim 1, wherein the POSS additive has theformula [(RSiO1.5)x]^#, wherein x refers to the stoichiometry of the composition and x may be in the range of 1-36, ^ indicates the composition forms a nanostructure, and # refers to the number of silicon atoms contained in the nanostructure (x).

25. The composite composition of claim 24, wherein R is an organic group selectedfrom the group consisting of alkyl, alkenyl, alkyne, aliphatic, aromatic, alcohol, epoxy, ether, ketone, acid, ester, peroxide, amine, amide, imide, azine, nitrile, isocyanite, sulfur, phosphorous, and halides 26. The composite composition of claim 1, wherein the POSS additive has theformula [(RSiO1.5)x(R1SiO1.5)y]^#, wherein x and y refer to the stoichiometry 17 #110059902v4of the composition and x and y may be in the range of 1-36, ^ indicates the composition forms a nanostructure, # refers to the number of silicon atoms contained in the nanostructure (x + y).

27. The composite composition of claim 26, wherein R and R1 are different organicgroups.

28. The composite composition of claim 1, wherein the POSS additive has theformula [(RSiO1.5)x(R1SiO1.5)y(R2SiO1.5)z]^#, wherein x, y, and z refer to the stoichiometry of the composition and x, y, and z may be in the rage of 1-36, ^ indicates the composition forms a nanostructure, # refers to the number of silicon atoms contained in the nanostructure (x + y +z).

29. The composite composition of claim 28, wherein R, R1, and R2 are differentorganic groups.

30. A method of modifying the physical properties of a polyolfein materialcomprising the steps of: (a) providing a polyolefin material; and(b) nonreactively incorporating polyhedral oligomeric silsesquioxane(POSS) nano cages into the polyolefin material at a loading level of 250- 800 ppm to form a composite material.

31. The method of claim 30, wherein a melt strength of the composite material isgreater than a melt strength of the polyolefin material.

32. The method of claim 30, wherein a melt fracture of the composite material isless than a melt fracture of the polyolefin material.

33. The method of claim 30, wherein a surface energy of the composite material isgreater than a surface energy of the polyolefin material.

34. The method of claim 30, wherein adhesion of the composite material is greaterthan adhesion of the polyolefin material.

35. The method of claim 30, wherein an adhesion strength of the composite materialis greater than an adhesion strength of the polyolefin material.

36. The method of claim 30, wherein a modulus of the composite material is higherthan a modulus of the polyolefin material, and wherein the POSS nano-cages disentangle the polyolefin.

37. The method of claim 36, wherein the modulus is a storage modulus.

38. The method of claim 36, wherein the modulus is a loss modulus.18 #110059902v439. The method of claim 30, wherein a modulus of the composite material is lowerthan a modulus of the polyolefin material, and wherein the POSS nano-cages disentangle the polyolefin.

40. The method of claim 39, wherein the modulus is a storage modulus.

41. The method of claim 39, wherein the modulus is a loss modulus.

42. The method of claim 30, wherein the polyolefin material comprisespolyethylene.

43. The method of claim 30, wherein the polyolefin material comprisespolypropylene.

44. The method of claim 30, wherein the polyolefin material comprises polylacticacid.

45. The method of claim 30, wherein the polyolefin material comprises nylon.

46. The method of claim 30, wherein the POSS nano-cages comprise homolepticPOSS.

47. The method of claim 30, wherein the POSS nano-cages comprise heterolepticPOSS.

48. The method of claim 30, wherein the POSS comprises i-butyl POSS.

49. The method of claim 30, wherein the POSS comprises phenyl POSS.

50. The method of claim 30, wherein the POSS comprises a silane selected fromthe group consisting of i-butyl, vinyl, octyl, i-octyl, phenyl, and methyl.

51. The method of claim 30, wherein the POSS additive has the formula [RSiO1.5]n,wherein n represents molar degree of polymerization and R represents organic substituent.

52. The method of claim 30, wherein the organic substituent is selected from thegroup consisting of hydrogen, siloxy, cyclic, aliphatic, olefinic, aromatic, alcohol, isocyanates, esters, amines, ketones, ethers, mercapto, peg, halide, silicone, halogen, and phosphazine.

53. The method of claim 30, wherein the POSS additive has the formula[(RSiO1.5)x]^#, wherein x refers to the stoichiometry of the composition and x may be in the range of 1-36, ^ indicates the composition forms a nanostructure, and # refers to the number of silicon atoms contained in the nanostructure (x).

54. The method of claim 30, wherein R is an organic group selected from the groupconsisting of alkyl, alkenyl, alkyne, aliphatic, aromatic, alcohol, epoxy, ether, 19 #110059902v4ketone, acid, ester, peroxide, amine, amide, imide, azine, nitrile, isocyanite, sulfur, phosphorous, and halides 55. The method of claim 30, wherein the POSS additive has the formula[(RSiO1.5)x(R1SiO1.5)y]^#, wherein x and y refer to the stoichiometry of the composition and x and y may be in the range of 1-36, ^ indicates the composition forms a nanostructure, # refers to the number of silicon atoms contained in the nanostructure (x + y).

56. The method of claim 30, wherein R and R1 are different organic groups.

57. The method of claim 30, wherein the POSS additive has the formula[(RSiO1.5)x(R1SiO1.5)y(R2SiO1.5)z]^#, wherein x, y, and z refer to the stoichiometry of the composition and x, y, and z may be in the rage of 1-36, ^ indicates the composition forms a nanostructure, # refers to the number of silicon atoms contained in the nanostructure (x + y +z).

58. The method of claim 30, wherein R, R1 , and R2 are different organic groups.20 #110059902v4

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