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Nowadays, most of the hydrogen is obtained from fossil fuels. At the same time, the effort and resources dedicated to the development of sustainable hydrogen manufacturing processes are rapidly increasing to promote the energy transition toward renewable sources. In this direction, a potential source of hydrogen could be hydrogen sulfide, produced as a byproduct in several processes, and in particular in the oil extraction and refinery operations. Methane reforming using H2S has recently attracted much interest for its economic and environmental implications. Its conversion, in fact, provides a viable way for the elimination of a hazardous molecule, producing a high-added value product like hydrogen. At the same time, some of the still open key aspects of this process are the coke deposition due to thermal pyrolysis of methane and the process endothermicity. In this work, the methane reforming with H2S by co-feeding sulfur is investigated through a detailed thermodynamic analysis as a way to alleviate the critical aspects highlighted for the process. A parametric analysis was conducted to assess the best thermodynamic conditions in terms of pressure, temperature, and feed composition. Changing the sulfur, H2S, and methane feed composition can enhance the system by improving the hydrogen production yield, reducing the carbon and sulfur deposition, increasing the H2S removal efficiency, and reducing the necessary thermal duty.

After having demonstrated their potential in biomedical applications, thermo-responsive block copolymers that are able to self-assemble into nano-objects in response to temperature modifications are becoming more and more appealing in other sectors, such as the oil and gas and lubricant fields. Reversible addition–fragmentation chain transfer (RAFT) polymerization-induced self-assembly has been demonstrated as a valuable strategy for producing nano-objects from modular block copolymers in non-polar media, required for the mentioned applications. Although the influence of the nature and size of the thermo-responsive block of these copolymers on the properties of the nano-objects is extensively studied in the literature, the role of the solvophilic block is often neglected. In this work, we elucidate the role of the main microstructural parameters, including those of the solvophilic portion, of block copolymers produced by RAFT polymerization in the hydrocarbon blend decane/toluene 50:50 v/v on the thermo-responsive behavior and colloidal properties of the resulting nano-objects. Two long-aliphatic chain monomers were employed for the synthesis of four macromolecular chain transfer agents (macroCTAs), with increasing solvophilicity according to the number of units (n) or length of the alkyl side chain (q). Subsequently, the macroCTAs were chain-extended with different repeating units of di(ethylene glycol) methyl ether methacrylate (p), leading to copolymers that are able to self-assemble below a critical temperature. We show that this cloud point can be tuned by acting on n, p,and q. On the other hand, the colloidal stability, expressed in terms of area of the particle covered by each solvophilic segment, is only a function of nand q, which provides a way for controlling the size distribution of the nano-objects and to decouple it from the cloud point.

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In the last years, the growing demand for tissues and organs led to the development of novel techniques, such as 3D bioprinting. This technique proved to be promising for both patient-specific and custom-made applications when using autologous cells, and for the creation of standardized models that in the future could be used for instance for high-throughput drug screening. Within this context, the formulation of bioinks that could provide reliable, reproducible, and replicable structures with good mechanical properties and high biocompatibility is a crucial challenge. In this work, the use of a thermoresponsive PEG-based formulation was investigated as a bioink, allowing its use for 4D bioprinting applications triggered by thermal changes. First, the polymer was synthesized by reversible addition-fragmentation chain transfer polymerization (RAFT), which allows for optimal control over the final properties of the polymer. Then, the printability for extrusion-based bioprinting of this formulation was assessed through in-situ imaging. Finally, the use of this polymer as bioink was tested by encapsulation of endothelial cells and evaluating cell distribution within the construct.

Tissue engineering techniques are central for the development of biomedical scaffolds, which are primarily employed in the biofabrication of various artificial human tissue and organ models. Bioprinting is a new technique of creating tissue constructs that can sustain cell proliferation. The development of printing techniques proceeds together with the development of the biomaterials to be printed, which is why studying the printability of these specific biomaterials must be explored. An appropriate hydrogel used as bioink should have numerous rheological, mechanical, and biological properties for producing appropriate tissue constructs. However, reaching the right trade-off between a desirable bioactivity and high printability is challenging, and despite numerous optimization studies for different materials, printing defects often occur during printing. Herein, methods are proposed to automatically identify these drifting processes in commonly used geometries and how they affected subsequent layers, as well as printing defects within each layer. Several structures were printed with standard commercial bioink as proof of concept. The constructs were analyzed using optical images from a coaxial camera. The images were then digitally processed to get geometrical data from which patterns of defectology to be monitored were derived. This automation should decrease the time in post-processing characterization of constructs and should provide a standardized tool to compare different bioinks.

The efficacy of several cell therapy products is directly impacted by trypsinization, which can diminish the engrafting capacity of transplanted cells by cleaving cell surface receptors. Thermoresponsive surfaces can alleviate this drawback, enabling temperature-driven and enzyme-free cell harvesting. However, the production of thermoresponsive surfaces relies on dedicated and complex equipment, often involving protocols dependent on high surface activation energies that prevent the development of scalable and universal platforms. In this work, we developed thermoresponsive copolymers incorporating styrene units that enable the copolymer adsorption on tissue culture polystyrene surfaces from an alcoholic solution in a short time, regardless of the vessel size and geometry, and without any particular equipment. In this way, the procedure can be performed with minimal effort by the end user on any surface. The thermoresponsive copolymers were synthesized via reversible addition–fragmentation chain transfer polymerization, providing high control over the polymer microstructure, a key parameter for tuning its cloud point and architecture. Block copolymers comprising a thermoresponsive segment and a polystyrene block exhibited optimal adhesion on conventional cell culture surfaces and permitted a more efficient temperature-mediated harvesting of adipose-derived stromal cells and Chinese hamster ovary cells compared to their statistical counterparts. To expand the application of this polymer deposition protocol to serum-free cell culture, we also considered the polymer modification with the tripeptide arginine-glycine-aspartic acid, known to promote the cell adhesion to synthetic substrates. The incorporation of this peptide enabled the collection in serum-free conditions of intact cell sheets from surfaces prepared shortly before their usage.

The market of cosmetic and personal care products is continuously growing its impact. In particular, the products that are currently driving this growth have a strict connection with fragrances (e.g., perfumes, detergents, body creams, and softeners). Since the fragrances are volatile molecules, very often, they are encapsulated in polymeric nanoparticles (NPs) that mediate their release and hence prolong the fragrance perception. Toward this aim, it is highly desirable to maximize the interaction between the carrier and the substrate, which would avoid the NP desorption following scrubbing and repeated washing. In the case of laundry products, limited NP desorption is also crucial to prevent the accumulation of nanoplastics in the environment, which is nowadays strictly regulated. Therefore, a thorough study highlighting the influence of the different physicochemical properties of the NPs on their adsorption behavior is urgently required. In this work, we synthesized polymer NPs with different sizes, surface charges, glass transition temperatures, and degrees of cross-linking through emulsion free-radical polymerization to investigate how these parameters affect the NP adsorption onto a textile substrate (composition: 90% cotton/10% elastane). This study can provide interesting guidelines in the design of new fragrance delivery systems as well as in the optimization of those already adopted in the market. Finally, we investigated the possibility of loading and mediating the release in air of limonene, one of the most common odorous molecules in the cosmetic field, overcoming its well-known volatility.

Astrogliosis has a very dynamic response during the progression of spinal cord injury, with beneficial or detrimental effects on recovery. It is therefore important to develop strategies to target activated astrocytes and their harmful molecular mechanisms so as to promote a protective environment to counteract the progression of the secondary injury. The challenge is to formulate an effective therapy with maximum protective effects, but reduced side effects. In this study, a functionalized nanogel-based nanovector was selectively internalized in activated mouse or human astrocytes. Rolipram, an anti-inflammatory drug, when administered by these nanovectors limited the inflammatory response in A1 astrocytes, reducing iNOS and Lcn2, which in turn reverses the toxic effect of proinflammatory astrocytes on motor neurons in vitro, showing advantages over conventionally administered anti-inflammatory therapy. When tested acutely in a spinal cord injury mouse model, it improved motor performance, but only in the early stage after injury, reducing the astrocytosis and preserving neuronal cells.

Synthetic substrates able to prevent the adhesion of cells, commonly referred to as nonfouling surfaces, are useful in a wide range of applications, including the culture of multicellular spheroids and the engineering of complex cell sheets. Nonfouling properties are commonly conferred to surfaces through superhydrophilic polymer-based coatings. At the same time, this type of treatment requires difficult, expensive, and time-consuming procedures, leading to high prices of the final product. In this perspective, the development of quick single-step methods to coat surfaces with nonfouling polymers would dramatically reduce the costs and increase the flexibility of such products. Moreover, this strategy would enable the process to be carried out directly by the end user. In this work, we report a fast and easy-to-use coating method to prevent the nonspecific adhesion of cells on tissue culture polystyrene (TCPS) surfaces. Our approach is based on the adsorption of poly(styrene-co-3-sulfopropyl methacrylate) copolymers comprising nonfouling hydrophilic moieties as well as functionalities that enhance the polymer adhesion to the substrate. The polymer adsorption is obtained from an aqueous mixture with a procedure that can be conveniently performed in short time. The kinetic of polymer adsorption as well as the effect of the polymer concentration was studied in order to reduce the time and cost of the entire procedure. Additionally, the polymer composition and the polymer density were optimized to completely avoid the adhesion of three different adherent cell lines, that is, CHO, A375-P, and HFF-1 cells.

Biodegradable polymer nanoparticles are an important class of materials used in several applications for their unique characteristics. In particular, the ones stabilized by zwitterionic materials are gaining increased interest in medicine as alternative to the more common ones based on poly(ethylenglycol) thanks to their superior stability and ability to avoid both the accelerated blood clearance and allergic reactions. In this work, a novel class of zwitterionic based NPs has been produced and a method to independently control the nanoparticle size, degradation time and polymer molecular weight has been developed and demonstrated. This has been possible by the synthesis and the fine tuning of zwitterionic amphiphilic block-copolymers obtained via the combination of ring opening polymerization and reversible addition-fragmentation chain transfer polymerization. The final results showed that when two block copolymers contain the same number of caprolactone units, the ones with longer oligoester lateral chains degrade faster. This phenomenon is in sharp contrast with the one seen so far for the common linear polyester systems where longer chains result in longer degradation times and it can be used to better tailor the degradation behavior of the nanoparticles.

Polymeric nanoparticles (NPs) are highly engineered nanoemulsions with applications in several fields. The control over NP surface chemistry, size (Dn), and molecular weight (MW) of the polymer they are made up of plays a paramount role in the optimization of their end-use performance. In this work, the theoretical basis to decouple the dependence between the NP Dn and MW has been presented, and an operative way has been demonstrated via ab initio reversible addition–fragmentation chain transfer (RAFT) emulsion polymerization (AIREP), a “living” heterogeneous process that adopts RAFT macro-surfmers: macromolecular chain transfer agents (CTA) produced via RAFT polymerization of amphiliphic monomers, such as surfmers. The possibility of obtaining the desired length of the lipophilic block or the length of the whole block copolymer and the NP Dn by choosing the correct length of the RAFT macro-surfmer has been assessed. It has been discovered that a wide range of Dn and MW can be achieved, but not very big NPs with very low copolymer MW; this limit is consistent with the physical and geometric constraints of the system.

Much evidence shows that acute and chronic inflammation in spinal cord injury (SCI), characterized by immune cell infiltration and release of inflammatory mediators, is implicated in development of the secondary injury phase that occurs after spinal cord trauma and in the worsening of damage. Activation of microglia/macrophages and the associated inflammatory response appears to be a self-propelling mechanism that leads to progressive neurodegeneration and development of persisting pain state. Recent advances in polymer science have provided a huge amount of innovations leading to increased interest for polymeric nanoparticles (NPs) as drug delivery tools to treat SCI. In this study, we tested and evaluated in vitroand in vivoa new drug delivery nanocarrier: minocycline loaded in NPs composed by a polymer based on poly-ε-caprolactone and polyethylene glycol. These NPs are able to selectively target and modulate, specifically, the activated proinflammatory microglia/macrophages in subacute progression of the secondary injury in SCI mouse model. After minocycline-NPs treatment, we demonstrate a reduced activation and proliferation of microglia/macrophages around the lesion site and a reduction of cells with round shape phagocytic-like phenotype in favor of a more arborized resting-like phenotype with low CD68 staining. Treatment here proposed limits, up to 15 days tested, the proinflammatory stimulus associated with microglia/macrophage activation. This was demonstrated by reduced expression of proinflammatory cytokine IL-6 and persistent reduced expression of CD68 in traumatized site. The nanocarrier drug delivery tool developed here shows potential advantages over the conventionally administered anti-inflammatory therapy, maximizing therapeutic efficiency and reducing side effects.

The reversible addition-fragmentation chain transfer polymerization is one of the most important techniques to control the molecular weight and the chain distribution of the polymers made via radical chemistry. Its application to the aqueous dispersed systems is an important step to improve the control of relevant polymers due to the advantages in the control of the reaction and to avoid the environmental issues related to the use of organic solvents. In this review, a brief overview on different techniques used to perform a well-controlled RAFT polymerization in aqueous dispersed systems is critically revised.

Fluorescent poly(ε-caprolactone)-based nanoparticles (NPs) have been synthesized and successfully loaded with a titanium organometallic compound as a mimic of a water-insoluble drug. The nature of this nanovector enabled us to combine the quantification of the metal in tissues after systemic administration in healthy immunocompetent mice by inductively coupled plasma mass spectroscopy (ICP-MS) followed by the visualization of NPs in organ sections by confocal microscopy. This innovative method of nanodrug screening has enabled us to elucidate the crucial parameters of their kinetics. The organometallic compound is a good mimic of most anticancer drugs, and this approach is an interesting starting point to design the relevance of a broad range of nanoformulations in terms of safety and targeted delivery of the cargoes.

Polymer nanoparticles (NPs) represent a promising way to deliver poorly water-soluble anticancer drugs without the use of unwanted excipients, whose presence can be the cause of severe side effects. In this work, a Cremophor-free formulation for paclitaxel (PTX) has been developed by employing PEGylated polymer nanoparticles (NPs) as drug delivery carriers based on modified poly(ε-caprolactone) macromonomers and synthesized through free radical emulsion polymerization. Paclitaxel was loaded in the NPs in a postsynthesis process which allowed to obtain a drug concentration suitable for in vivo use. In vivo experiments on drug biodistribution and therapeutic efficacy show comparable behavior between the NPs and the Cremophor formulation, also showing good tolerability of the new formulation proposed.

This paper describes a model based analysis of a differential planar servomechanism (two degrees of freedom); this system is meant to achieve high performance as regards the positioning precision (meant as both repeatability and accuracy) keeping a relative high dynamic.

Summary:Quantum chemistry was applied to the free radical polymerization of Vinyl Chloride with the aim of elucidating the reaction kinetics and especially the formation of structural defects and low molecular weight polymer. The radical reactions were studied using the Density Functional Theory. All calculations were performed with B3LYP functionals and in particular the 6‐31G(d,p) basis set was selected to evaluate the exchange and correlation energies. The computational method was first validated by predicting the rate constant of the propagation step and comparing the calculated values to experimental ones. Then intramolecular chain transfer, β‐scission and branching reactions were also investigated, due to their direct connection with the production of defects in the growing chains. A comparison of the evaluated kinetic constants of such secondary reactions with other computational evaluations and experimental data was finally made.

Summary:The potentials of computational techniques based on quantum mechanics, to support and complement the experimental analysis, are examined. Mechanisms and reaction paths involved in the free radical polymerization of widely used monomers are studied through a computational approach based on Density Functional Theory (DFT). First, the attention is focused on the initiation kinetics in order to evaluate the role of the initiators in the polymerization process. Methyl acrylate, methyl methacrylate, acrylonitrile, and styrene homopolymerization using different initiators are studied. Then, propagation kinetics is investigated. In particular, the propagation kinetic rate constants for different kinds of acrylates, methacrylates and acetates are calculated and compared with experimental data reported in the literature. The same computational approach is applied to the study of secondary reactions (backbiting, beta‐scission) occurring during free radical polymerizations. Finally, the same methodologies are applied to copolymer systems, with emphasis on the evaluation of the role of penultimate effect. The copolymers vinyl acetate/methyl methacrylate and styrene/methyl methacrylate are investigated as system characterized by weak and strong penultimate effect, respectively.

Initiation kinetics in free radical polymerization is investigated using density functional theory. Thermodynamic and kinetic parameters of the initiation reactions are predicted, and the role of the initiators in the polymerization process is evaluated. Methyl acrylate, methyl methacrylate, acrylonitrile, and styrene homo‐polymerizations with different initiators are studied. Reaction enthalpy and activation energy for each reaction between monomer and the radical fragments arising from the initiators have been determined. The initiation kinetic constants for all of these initiation reactions are evaluated and compared with both computational and experimental propagation kinetic constants of each monomer.

HPLC is applied and assessed as an effective tool to investigate both the production of PLA by polycondensation and its corresponding degradation. A new HPLC calibration procedure, through which it is possible to fully characterize LMW PLA samples by determining the concentration of each individual oligomer, is developed. A comparison between HPLC, 1H NMR spectroscopy and nonaqueous solution titration is also reported in order to confirm the reliability of the proposed method. Finally, the proposed analytical technique is applied to monitor the development of a polycondensation reaction performed at 150 °C and 133.3 mbar for 12 h.

The decomposition kinetics of chlorosilanes have been so far investigated up to the lower molecular weight fragments, not regarding the generation of telomeres. In this work Quantum Chemistry was employed to investigate gas phase polymerization of chlorosilanes in operating conditions proper to silicon epitaxy. Thermodynamic and kinetic parameters, molecular structures and transition state geometries were determined with Density Functional Theory (DFT), resulting in a series of fast condensation-reactions bringing to the production of telomeres. In particular, a large number of linear, branched and cyclic silicon- compounds were analyzed (up to Si6Clx species). Finally the kinetic scheme was embedded in a reactor simulation code, where significant amounts of such species were obtained.

Summary:In this work, Quantum Chemistry is applied to investigate the propagation kinetics in free radical polymerization. Energies, structures and transition state geometries are determined using density functional theory, which combines good accuracy with reasonable computational demand. In particular, B3LYP functional is used to evaluate the exchange and correlation energy with the 6‐311+G(d,p) basis sets. The capabilities of the approach with respect to the prediction of the kinetic constants of elementary processes relevant to polymeric systems (propagation reactions) is first tested using literature experimental data as reference values.1 Namely, two different monomers of industrial relevance have been selected, acrylonitrile and styrene. For such systems, the effect of chain‐length on the propagation rate coefficient is examined. Finally, for the selected monomer pair, the relative reactivity (so‐called reactivity ratios) is also analyzed, in particular considering the penultimate effect.

Summary:A mathematical model for the polycondensation of lactic acid accounting for water removal by diffusion is developed. The corresponding kinetic parameters are estimated by performing experiments under different sets of reaction conditions in open system. The model results are compared with the experimental ones and, after validating the model, parametric simulations are further carried out to understand the effects of operating conditions such as reaction temperature, catalyst activity, and reaction pressure.

In this work we used quantum mechanics hybrid models (QM/QM) to investigate the high-temperature polymerization of styrene with the aim of elucidating its elementary chemistry. High and low quality quantum mechanics calculations were performed at the B3LYP/6-31g(d,p) and PM3 levels, respectively. Reaction kinetic constants were calculated for oligomers composed of up to 6 styrene units with classic transition state theory on potential energy surfaces determined at the QM/QM level. The capability of this approach to predict kinetic constants of elementary processes relevant to styrene polymerization was validated through the satisfactory comparison with well-known experimental data. One of the main results of this study is that a new kinetic route is proposed to describe the polymer growth mechanism, in which the succession of backbiting and scission reactions plays a critical role. In particular we found that the 7:3 backbiting reaction can proceed fast and influence significantly the polymer weight distribution. Finally, the so evaluated kinetic constants were introduced in a polymerization reactor model and used to compare the distribution of the produced oligomers measured experimentally with that predicted from first principles. The agreement with experimental data is good, suggesting that the proposed approach provides a valuable tool to investigate the kinetics of polymerization systems for which experimental data on elementary reactions are not available.

Over the last few years, oil companies have devoted much effort to decrease the amount of water that is pumped up with oil, especially from mature reservoirs, where the water production is huge. In addition to reducing the profit margin, the water extracted from an oil field is polluted by different organic and inorganic compounds and must be properly treated before being discharged or reinjected. Alternatively, it must be disposed of with high treatment and/or disposal costs. To overcome costs associated with water treatment/disposal, mechanical and chemical strategies aimed at reducing the amount of extracted water (i.e., water shut-off) are applied. Among them, hydrophilic polymeric micro- and nanogels are promising materials that are gaining increasing interest. They are three-dimensional networks able to retain water by increasing in size and thus creating a physical barrier to the water flowing. In this work, nano- and microabsorbent particles made up of crosslinked poly(methacrylic acid-co-oligo(ethylene glycol) methyl ether methacrylate) p(MAA-co-OEGMA) were synthesized via inverse suspension polymerization in Lamix, an aromatic-free hydrocarbon blend. The formulation was optimized in terms of OEGMA mole fraction to achieve a high swelling in seawater and hence high efficacy in the water shut-off. Finally, the suspension was modified to be produced on a ton scale and injected into an open-hole, partially depleted oil reservoir for a first pilot field test. One-year monitoring was conducted by evaluating the oil productivity as well as the water fraction (i.e., water cut) under conventional extraction procedures. This trial assessed a 30% decrease in the water cut, as well as an increase in the oil production from 5 to 30 m3/day. This confirmed the developed microgels as a promising tool for water shut-off.

Polyester-based nanoparticles (NPs) are among the most adopted drug delivery systems developed so far. This is mainly due to their ability to increase the bioavailability of the loaded therapeutics, to prevent the adverse effects often associated with their use, and to eliminate the toxic excipients necessary to formulate them. In addition, these NPs are biodegradable under physiological conditions thus avoiding the polymer accumulation in the body. However, the complexity in the formulation and storage hampers the cost-effective use of these formulations reducing their availability among the patient population. In addition, the manifold drugs available on the market, characterized by different chemical structures and charges, impose the continuous optimization of different delivery systems for their efficient formulation. Therefore, tunable NPs able to encapsulate different drugs with high loading efficiencies and to modulate their release after administration are urgently needed. In this work, a method to formulate different drugs directly at the point of care using only a syringe and starting from preformed NPs has been developed. Highly tunable zwitterionic NPs have been synthesized via the combination of ring opening polymerization and reversible addition–fragmentation chain transfer emulsion polymerization and then used to load paclitaxel, doxorubicin, or ibuprofen with high efficiency. The controlled release of such therapeutics has been achieved by tuning the characteristics of the NPs, in particular by the addition of charged groups.

Cover:Photechemical decomposition of 2,2‐dimethoxy‐2‐phenyl acetophenone (DMPA) leads to the formation of benzoyl and methyl radicals. Reactivity of these radical species as initiator fragments in the free radical polymerization of different monomers, such as acrylonitrile and styrene, is studied using quantum chemistry. Further details can be found in the article by M. Dossi, G. Storti, and D. Moscatelli*on page 170.

The decomposition kinetics of chlorosilanes have been so far investigated up to the lower molecular weight fragments, not regarding the generation of telomeres. In this work Quantum Chemistry was employed to investigate gas phase polymerization of chlorosilanes in operating conditions proper to silicon epitaxy. Thermodynamic and kinetic parameters, molecular structures and transition state geometries were determined with Density Functional Theory (DFT), resulting in a series of fast condensation-reactions bringing to the production of telomeres. In particular, a large number of linear, branched and cyclic silicon- compounds were analyzed (up to Si6Clx species). Finally the kinetic scheme was embedded in a reactor simulation code, where significant amounts of such species were obtained.