Physical Bonds Research Articles

Molecular Design: Network Architecture and Its Impact on the Organization and Mechanics of Peptide-Polyurea Hybrids.

Nature has achieved controlled and tunable mechanics via hierarchical organization driven by physical and covalent interactions. Polymer-peptide hybrids have been designed to mimic natural materials utilizing these architectural strategies, obtaining diverse mechanical properties, stimuli responsiveness, and bioactivity. Here, utilizing a molecular design pathway, peptide-polyurea hybrid networks were synthesized to investigate the role of architecture and structural interplay on peptide hydrogen bonding, assembly, and mechanics. Networks formed from poly(β-benzyl-l-aspartate)-poly(dimethylsiloxane) copolymers covalently cross-linked with a triisocyanate yielded polyurea films with a globular-like morphology and parallel β-sheet secondary structures. The geometrical constraints imposed by the network led to an increase in peptide loading and ∼7x increase in Young's modulus while maintaining extensibility (∼160%). Thus, the interplay of physical and chemical bonds allowed for the modulation of resulting mechanical properties. This investigation provides a framework for the utilization of structural interplay and mechanical tuning in polymer-peptide hybrids, which offers a pathway for the design of future hybrid biomaterial systems.

The Influence of the Acid–Base Balance of the Surface of Silica Filler Particles on the Structure and Properties of Composites Based on Nitrile Butadiene Rubber

The acid–base balance of the surface of silica filler (SF) particles of different grades was determined, and its influence on the structure and properties of mixes based on nitrile butadiene rubber (NBR) was investigated. A near-linear correlation was found between the proneness of the SF particles to flocculate and the concentration of acid centres (ACs) on their surface, in the absence of any pronounced influence on this index of the degree of dispersion of the filler particles. Of all the SF grades investigated, the greatest capacity to form flocculation structures is exhibited by a filler characterised by a higher SF concentration. Increase in the SF concentration leads to an increase in the relative content of physical and covalent bonds in binary mixes of NBR and SF. It is shown that, to reduce the negative effects associated with the formation of flocculation structures, including in the induction period of vulcanisation, it is necessary to select a filler with a lower concentration of these centres.

Telechelic Polymer Hydrogels: Relation between the Microscopic Dynamics and Macroscopic Viscoelastic Response.

Telechelic polymers, that is, hydrophilic polymers with hydrophobic end-groups, spontaneously form hydrogels consisting of interconnected micelles. Here we investigate the relation between the microscopic dynamics determining the connectivity, that is, the lifetime of the physical bonds and the resulting rheological properties. This is achieved by quantitatively relating the chain exchange kinetics measured by time-resolved small-angle neutron scattering (TR-SANS) and the mechanical response obtained from linear oscillatory shear measurements. The results show that the characteristic relaxation time obtained from rheology coincides exactly with TR-SANS at intermediate concentrations. The activation energy, Ea, is concentration-independent and remain exactly the same as for TR-SANS. Upon crossing the melting point, a discrete change in activation energy is observed showing the contribution from the enthalpy of fusion to the release/debridging process. The results clearly show that the mechanical response and connectivity indeed are controlled by molecular exchange processes. The relaxation time at the lowest concentration is found to be faster in rheology as compared to TR-SANS, which can be quantitatively attributed to entropic forces arising from conformational deformation of bridging chains.

A Novel Propolis Wax‐Based Organogel: Effect of Oil Type on Its Formation, Crystal Structure and Thermal Properties

AbstractIn this work, the potential application of propolis wax (PW) as a novel organogelator was investigated in different oils (canola, sesame, sunflower and flaxseed oil). PW at 2% (w/w) concentration produced a thick organogel at 5, 10 and 15 °C, with needle‐like crystals, suggesting that PW is a relatively efficient structuring agent for organogel formation. The oil binding capacity of the organogel with canola oil was lower than that of the other organogels, and the gelling time of flaxseed organogel with lower oil viscosity was shorter. The X‐ray diffraction measurements of the crystals showed β′‐form crystals, with no influence of oil type. In FTIR results, no chemical intermolecular interactions that were observed indicated physical bonds in the organogel network. DSC analysis was carried out to obtain greater insight into the thermal behavior of PW organogels. No significant differences were observed. The textural properties of PW organogels were stable over 30 days of storage. Flaxseed oil organogel had the greatest firmness and stickiness. These results showed the effect of oil viscosity on PW gel behavior.

A rheological study of molecular and supramolecular organization of chitosan succinamide in a mixed water–etanol solvent

An approach based on quality reduction of the solvent, namely, the use of mixed water–ethanol solvents of variable volume ratio was used for control over the aggregation and formation of a physical net of bonds in chitosan succinamide solutions. A study of the molecular and supramolecular organization of chitosan succinamide in solution showed that this polymer, which does not aggregate in a dilute (to the crossover point) aqueous solution, aggregates in a mixed water–ethanol solvent even at high dilution. Polymer structurization in solution is accompanied by the formation of an additional net of physical bonds, whose nodes are aggregates of chitosan succinamide macromolecules formed in the mixed solvent. It leads to earlier formation of viscoelastic properties, which is ultimately reflected by the regularities of some physicochemical properties of materials formed from solution.

FILM MATERIALS WITH TIAMULIN FUMARATE ON THE BASIS OF POLYURETHANEUREAS, WHICH CONTAINING IN THE STRUCTURE FRAGMENTS OF A COPOLYMER OF N-VINYLPYRROLIDONE WITH VINYL ALCOHOL

A series of hydrophilic film materials with tiamulin fumarate based on polyurethaneureas (PUU) which contain in its structure fragments of the copolymer N-vinylpyrrolidone and vinyl alcohol at various ratios of components. The structure of the obtained polymer materials was investigated by the method of IR-spectroscopy. It was established that immobilization of tiamulin fumarate occurs due to physical bonds. The introduction of the tiamulin fumarate in to PUU leads to increased physical and mechanical properties which are within the 3,0-7,3 MPa. Polymeric materials with tiamulin fumarate synthesized at ratio GMDA to VP-VA as 70 to 30 characterized by most high values of strength (7.3 MPa) and the relative elongation at break (100%) and can be offered for medical and biological tests.

Family Formation and the Home

Intergenerational families, voluntary kin groups, non-conjugal adult room-mates, and unmarried couples with or without children, all build domestic family lives together without formal and consistent legal recognition. The variety of families that provide benefits to dependents and mutual support to adults is constantly evolving; but, living together and creating a joint home has always been a central aspect of family life. As traditional family life tied to marriage and biology is continuously challenged, and alternative forms of family formation are developed, the significance of the role of the home plays in creating legally significant ties has been largely overlooked. While domesticity has been intermittently used as a tool in defining family, we will demonstrate that the ways in which home sharing creates family rights and obligations is riddled with inconsistencies and conflicts. On the one hand, certain welfare-based entitlements and zoning cases use flexible standards for determining family based on domesticity. However, on the other hand, even the rare recognition of private rights and obligations among those who cohabit occurs when sexuality or reproduction are also involved in a manner that more closely mimics traditional marriage. Generally, domesticity is assumed to include sexuality and the focus on family formation has centered on the sexuality involved. However, in this article we consider how joint lives that are based under a common roof whether or not they include sexual relations can include many of the supports and normative benefits of family life. We will demonstrate based on social science studies and taking into account both the benefits and risks of home sharing, how domesticity has its own normative benefits and ways of creating emotional and physical bonds apart from sex. Finally, this article will lay out different possibilities for how the law can recognize and support the role home sharing plays in creating familial lives that provide mutual support, stability and other important benefits over an extended and stable period of time. Keeping in mind both the desire to foster diversity and autonomy and protect those who are most vulnerable, this article considers options for legal recognition of the status of domesticity in family formation. These alternatives include consideration of how vulnerability could justify the imposition of obligations and rights upon sexual or non-sexual cohabitants and how registrations systems can provide solutions to those seeking legal recognition of the mutual support systems and family lives they create in a diverse manner by sharing a home with loved ones and/or long-term trusted friends.

Morphology of the Wind Catchers in the Laft Port

<p>Discussing morphology in one of the traditional architectural element of Iran without analyzing its elements and recognizing its components, forms and colors would be an incomplete matter. The geometry of this architecture is the result of its fundamental components and elements not being formed in the designer’s mind all of a sudden in a constructive and unified process; rather it is the result of a gradual practical and constructive method. Its components including physical and geometrical features exert significant effect on the end result of the overall volume. The formation process in nature is often carried out by the help of a structure or some structures. Like nature, formation of volumes in Iran’s traditional architecture follows the same rules. The morphologies of the traditional architecture as well as the modern architecture are fundamentally different with each other from this perspective. This means that the former is accomplished through motion of basic, constructive and standardized elements in space while the latter is realized through a mental and abstract process. Nevertheless, recognizing the physical texture of traditional architecture has a considerable effect on its morphology. Physical, chemical, and geometrical bonds maintain the natural forms in the nature and organized them, but traditional architecture follows those natural rules which are mostly in physical and geometrical bonds because its constructional materials are mainly natural elements and less synthetic. A traditional architect is in search for the harmony rules of the standardized constructional components (masonry materials) so that he can find out a relatively stable equilibrium against the applied forces. These rules have become available for architects through experience and observance of the nature and also the introductory geometrical analyses and eventually, his attempt to counter the force of gravity is reflected in the general form of the work. This attempt in the form of the used shapes is perceivable by the viewer of this architectural work and based on this perception, an aesthetical relation is created between the observer and the work. Wind Catcher has been among the historical elements of Iranian traditional architecture in the hot and dry as well as hot and humid regions of this country which consist of a tower higher than elsewhere in houses and being located on the roofs and water storages to fulfill the role of controlling wind flow and conducting it into the inner space of the houses. Existence of various decorative forms and natural colors used in the facades of the wind catchers, the necessity to approach and analyze them, also maintenance and usage of these elements as well as making them known to the researchers at the present time led to the formation of this study being conducted through a field research by attending the context, having interviews with the locals and analyzing and drawing 50 samples of the present wind catchers to meet the main purpose of the study more accurately which was “analyzing the function and recognizing the motifs and colors” used in the wind catchers. Studies on recognition of the motifs and colors used in the wind catchers of the Sothern Iran (Laft) have not been done so far and only a book entitled “Architecture of Laft Port” published by “Tehran University” Publications in 2001 is available. Some general studies have also been conducted sporadically by Iranian and Arab researchers. Therefore, having conducted this study toward completing the studies about this port, in the first part entitled “An Overview on Wind Catcher and its Function”, we have dealt with location of wind catcher in the house plans. In the second part, i.e., “Morphology of the Wind Catchers”, their constructional elements and components and also classification of their motifs-that are divided in two natural and geometrical groups were analyzed. Finally, the results indicated that since this Port is located adjacent to the Persian Gulf and surrounded by nature, most of the adornments used in the wind catchers are abstractly inspired from nature and sea and their colors are made of vernacular materials.</p>

Neighbourhood attachment revisited: Middle-class families in the Montreal metropolitan region

Migration, mobility, globalisation and individualisation have transformed the way people relate to space by affecting their physical, social and emotional bonds to place. Yet, does it mean that place attachment is due to wane and that the neighbourhood does not matter nowadays? The article is tackling this question by addressing the underexplored neighbourhood attachment and the residential choices of young middle-class families in Montreal Census Metropolitan Area. Empirical results are drawn from in-depth interviews with immigrant and non-immigrant households in a comparative perspective between a peri-urban and near-suburban neighbourhood in recent ethnic transition. We explore three types of neighbourhood attachment: physical and social as underlined in the literature, but we also suggest the importance of accounting for the symbolic dimension of neighbourhood attachment. Findings reveal how families display neighbourhood attachment through an extensive use of neighbourhood amenities (physical), embedded social ties (social) and distinctive lifestyles convergent with the representations of middle-class family life (symbolic). Unlike narratives of middle-classes’ place detachment and withdrawal from neighbourhood life, our case study of ‘middle’ middle-class neighbourhoods suggest that the neighbourhood preserves its importance, but that neighbourhood attachment takes different forms and that these forms differ among urban and suburban families. It is argued that what residents believe urban and suburban life should be and their values and identities associated with it needs further investigation, given their considerable role in neighbourhood attachment and residential choices of middle-classes families.

Gelatin Microgel Incorporated Poly(ethylene glycol)-Based Bioadhesive with Enhanced Adhesive Property and Bioactivity.

Up to 7.5 wt % of chemically cross-linked gelatin microgel was incorporated into dopamine-modified poly(ethylene glycol) (PEGDM) adhesive to simultaneously improve the material property and bioactivity of the PEG-based bioadhesive. Incorporation of gelatin microgel reduced cure time while it increased the elastic modulus and cross-linking density of the adhesive network. Most notably, the loss modulus values for microgel-containing adhesive were an order of magnitude higher when compared to microgel-free control. This drastic increase in the viscous dissipation ability of the adhesive is attributed to the introduction of reversible physical bonds into the adhesive network with the incorporation of the gelatin microgel. Additionally, incorporation of the microgel increased the adhesive properties of PEGDM by 1.5- to 2-fold. From in vitro cell culture studies, the composite adhesive is noncytotoxic and the incorporation of microgels provided binding site for promoting fibroblast attachment and viability. The subcutaneous implantation study indicated that the microgel-containing PEGDM adhesive is biocompatible and the incorporated microgels provided pockets for rapid cellular infiltration. Gelatin microgel incorporation was demonstrated to be a facile method to simultaneously enhance the adhesive property and the bioactivity of PEG-based adhesive.

A review: role of interfacial adhesion between carbon blacks and elastomeric materials

Abstract Carbon blacks (CBs) have been widely used as reinforcing materials in advanced rubber composites. The mechanical properties of CB-reinforced rubber composites are mostly controlled by the extent of interfacial adhesion between the CBs and the rubber. Surface treatments are generally performed on CBs to introduce chemical functional groups on its surface. In this study, we review the effects of various surface treatment methods for CBs. In addition, the preparation and properties of CB-reinforced rubber composites are discussed. Key words: rubber, carbon blacks, surface treatments, interfacial adhesion 1. Introduction Rubber exhibits superior viscoelastic properties and improves the lifespan of products which continue to be transformed. At first, natural rubber (NR), which is composed of isoprene monomers, was obtained from nature. Later, as industries developed, synthetic rubbers were produced to supplement the production of NR. In particular, studies have been conducted on a new kind of rubber that is made of butadiene, namely, a copolymer of acrylonitrile butadiene rubber (NBR) and styrene butadiene rubber (SBR) as shown in Fig. 1 [1-6].However, rubber lacks sufficient physical strength, which makes it unsuitable for various applications. For this reason, fillers, such as carbon materials and silica, are added to rubber to form rubber composites with improved mechanical behaviors [7-27].In recent years, carbon materials have been widely used as reinforcing agents in high-per -formance composite materials [28-35], adsorbents [36], electrochemistry [37], and energy storage materials [38]. Among various carbon materials used as reinforcing agents, carbon blacks (CBs) are the oldest carbon derivatives produced by the incomplete combustion of petroleum products, such as fluid catalytic cracking tar and coal tar. Moreover, the particle size, structure, and surface conditions of CBs (Fig. 2) make them popular reinforcing agents [19-21].CBs contain more than 95% amorphous carbon, and their particle sizes vary from 5 to 500 nm. The physical properties of CBs vary with the production method and the raw materials used, which makes them suitable for applications in various fields. The mixing ratio of CBs in automobile tires is 50%, while that in other rubber products is approximately 30%. Rela-tively large amounts of reinforced CBs should be added to NR to attain acceptable mechani-cal properties. Cohesion occurs between CB particles due to chemical and physical bonds. The chemical composition of CB aggregates is 90%–99% carbon, 0.1%–1.0% hydrogen, 0.2%–2.0% oxygen, and a small amount of sulfur and ash. In addition, oxygen-containing functional groups, such as the carboxyl, hydroxyl, and quinine groups, exist on the surfaces of CBs. These are called surface functional groups. These surface functional groups increase the chemical and physical bonding between the CBs particles and the rubber matrix [39-43]. Therefore, the addition of CBs to rubber results in the formation of composites with im-

Strong Physical Hydrogels from Fibrillar Supramolecular Assemblies of Poly(ethylene glycol) Functionalized Hexaphenylbenzenes

Gel formation without chemical cross-links requires strong physical bonds, as observed in diverse molecular and macromolecular systems or supramolecular assemblies above a critical concentration. Here, we present a new molecular amphiphile of propeller-like hexaphenylbenzene derivative bearing two short poly(ethylene glycol) (PEG) chains which forms reversible physical gels comprising long (∼2.2 μm) bundles of hydrogel fibrils in coexistence with spherical micelles. Combination of topological (entanglement-like) interactions between the fibers and specific hydrophobic interactions due to the helicity of the PEG chains is proposed to account for the hydrogelation in the semidilute regime. The present supramolecular hydrogels, which are based on small molecules, exhibit extraordinary properties with an exceptionally strong dependence of the shear modulus on concentration, akin to the behavior of ultrahigh molecular weight cellulose-based fibers.

Discontinuous nature of the repulsive-to-attractive colloidal glass transition.

In purely repulsive colloidal systems a glass transition can be reached by increasing the particle volume fraction beyond a certain threshold. The resulting glassy state is governed by configurational cages which confine particles and restrict their motion. A colloidal glass may also be formed by inducing attractive interactions between the particles. When attraction is turned on in a repulsive colloidal glass a re-entrant solidification ensues. Initially, the repulsive glass melts as free volume in the system increases. As the attraction strength is increased further, this weakened configurational glass gives way to an attractive glass in which motion is hindered by the formation of physical bonds between neighboring particles. In this paper, we study the transition from repulsive-to-attractive glasses using three-dimensional imaging at the single-particle level. We show how the onset of cage weakening and bond formation is signalled by subtle changes in local structure. We then demonstrate the discontinuous nature of the solid-solid transition, which is marked by a critical onset at a threshold bonding energy. Finally, we highlight how the interplay between bonding and caging leads to complex and heterogeneous dynamics at the microscale.

Development, Characterization, and Utilization of Food-Grade Polymer Oleogels.

The potential of organogels (oleogels) for oil structuring has been identified and investigated extensively using different gelator-oil systems in recent years. This review provides a comprehensive summary of all oil-structuring systems found in the literature, with an emphasis on ethyl-cellulose (EC), the only direct food-grade polymer oleogelator. EC is a semicrystalline material that undergoes a thermoreversible sol-gel transition in the presence of liquid oil. This unique behavior is based on the polymer's ability to associate through physical bonds. These interactions are strongly affected by external fields such as shear and temperature, as well as by solvent chemistry, which in turn strongly affect final gel properties. Recently, EC-based oleogels have been used as a replacement for fats in foods, as heat-resistance agents in chocolate, as oil-binding agents in bakery products, and as the basis for cosmetic pastes. Understanding the characteristics of the EC oleogel is essential for the development of new applications.

Fracture of dual crosslink gels with permanent and transient crosslinks

We have carried out systematic fracture experiments in a single edge notch geometry over a range of stretch rates on dual crosslink hydrogels made from polyvinyl alcohol chains chemically crosslinked with glutaraldehyde and physically crosslinked with borate ions. If the energy release rate necessary for crack propagation was calculated conventionally, by using the work done to deform the sample to the critical value of stretch λc where the crack propagates, we found that the fracture energy Γ peaks around λ̇∼0.001s−1 before decreasing sharply with increasing stretch rate, in contradiction with the measurements of crack velocity. Combining simulations and experimental observations, we propose therefore here a general method to separate the energy dissipated during loading before crack propagation, from that which is dissipated during crack propagation. For fast loading rates (with a characteristic strain rate only slightly lower than the inverse of the typical breaking time of physical bonds), this improved method to estimate a local energy release rate glocal at the onset of crack propagation, gives a value of the local fracture energy Γlocal which is constant, consistent with the constant value of the crack propagation velocity measured experimentally. Using this improved method we also obtain the very interesting result that the dual crosslink gels have a much higher value of fracture energy at low loading rates than at high loading rates, contrary to the situation in classical chemically crosslinked elastic networks.

Morphology and molecular dynamics investigation of PDMS adsorbed on titania nanoparticles: Effects of polymer molecular weight

Morphology, thermal transitions and molecular dynamics of polydimethylsiloxane (PDMS) adsorbed onto low specific surface area (25m2/g) spherical-like titania (TiO2) nanoparticles were studied employing adsorption–desorption nitrogen isotherms, morphology (SEM), calorimetry (DSC) and dielectric (BDS) techniques. The initial titania particles (crystallites of 40–140nm in diameter) were found to aggregate forming voids of a broad range. PDMS was adsorbed in the interior of voids in aggregates and onto external surfaces of the aggregates. With nanoparticles content increasing an increase in the glass transition temperature, Tg, is observed in DSC, accompanied by a broadening of the glass transition step and a decrease in the heat capacity step, ΔCp. According to BDS the interfacial polymer fraction is larger and exhibits slower dynamics (αint relaxation) in the case of shorter PDMS chains (∼22 monomers/chain) as compared to longer chains (∼105 monomers/chain). Changes in the interfacial polymer fraction correlate well with changes in the specific surface area of the aggregates, as recorded by gas molecules adsorption–desorption, and with morphology (SEM). Comparison with previous results obtained with PDMS-based nanocomposites suggests that interfacial polymer fraction and dynamics are dominated by the concentration of polymer–particle contact points (increased for shorter chains due to more free chain ends), rather than by the strength of polymer–filler physical bonds.

Patriarchal Hierarchies of Power and the Subordination of Women: Real Doll as a Replacement of Woman Figure

The social structure of the family has always been in the state of transformation. In the past centuries, the nuclear family was replaced with a Patriarchal Family which lasted for only two centuries from 16th to the beginning of 18th century. In this new structure of the family, men were privileged to play the role of the master and the women were marginalized and subordinated. Recent years, however, has witnessed a re-adjustment of this order towards a more equal distribution of power relations. These changes in family structure has ever since initiated new conflicts leading to establishment of the physical and psychological bonds between men and dolls. The present study aims to find out the major socio-psychological reasons behind this conflict. In a qualitative library based study, the researchers attempt to analyse the video interview of some of the doll-owners. In the survey conducted in this study, the video of “Guys and Dolls”, BBC Video Documentary, has been shown to 10 participants, five male and five female. Then, a questionnaire was distributed to ask for their opinion based on their gender. The findings of this analysis reveal that women can hardly accept the notion of using dolls as replacement to real partners in comparison with men. On the contrary, the male participants advocated the employment of dolls as sexual replacement for the real woman figure. Keywords: Patriarchy, Real Doll, Oedipus complex, Female Subordination, Family

Chemically modified bitumens with enhanced rheology and adhesion properties to siliceous aggregates

Moisture damage is one of the major premature failures that worsens the performance and shortens service life of pavements. This research assesses the effect that two chemical modifiers (thiourea and an isocyanate-functionalized castor oil prepolymer) exerts on the bitumen rheology and on the resistance to potential moisture damage of asphalt mixtures based on siliceous aggregates. Both thiourea and the isocyanate-based prepolymer improve the viscous and viscoelastic behaviours of bitumen at high in-service temperatures, particularly the isocyanate-based reactive modifier. Likewise, the visual inspection of the degree of bitumen coating on loose mixtures exposed to water in a “rolling bottle” test, and further surface free energy measurements, showed that the bitumen modification by the isocyanate-based prepolymer seems to reduce moisture-induced damage on siliceous aggregates. Conversely, thiourea-based modification increases sensitivity of the bitumen–aggregate mixture to water. Different adhesion mechanisms, based on chemical or physical bonds with the aggregate surface, have been proposed for each modifier.

Erratum to: The Consequences of Tariff Reduction for Economic Activity and Inequality

The recent increase in trade liberalization has had substantial distributional consequences, although the direction of the relationship and the mechanism driving it has been open to debate. This paper analyzes the impact of tariff reductions on the dynamics of wealth and income inequality in a growing economy in which agents accumulate both physical capital and international bonds. Our study, which comprises a combination of formal analysis, supplemented with numerical simulations, suggests that in the long run the tariff reduction will be expansionary and be associated with both a permanent reduction in wealth inequality but an increase in income inequality, the magnitudes of which depend upon the speed with which the tariff reduction is implemented.

Fragmentation and depolymerization of non-covalently bonded filaments.

Protein molecules often self-assemble by means of non-covalent physical bonds to form extended filaments, such as amyloids, F-actin, intermediate filaments, and many others. The kinetics of filament growth is limited by the disassembly rate, at which inter-protein bonds break due to the thermal motion. Existing models often assume that the thermal dissociation of subunits occurs uniformly along the filament, or even preferentially in the middle, while the well-known propensity of F-actin to depolymerize from one end is mediated by biochemical factors. Here, we show for a very general (and generic) model, using Brownian dynamics simulations and theory, that the breakup location along the filament is strongly controlled by the asymmetry of the binding force about the minimum, as well as by the bending stiffness of the filament. We provide the basic connection between the features of the interaction potential between subunits and the breakup topology. With central-force (that is, fully flexible) bonds, the breakup rate is always maximum in the middle of the chain, whereas for semiflexible or stiff filaments this rate is either a minimum in the middle or flat. The emerging framework provides a unifying understanding of biopolymer fragmentation and depolymerization and recovers earlier results in its different limits.